Rules. Lets play for fun. This is the cbs evening news with scott captioning sponsored by cbs this is the cbs evening news with scott pelley. Pelley isis has been steadily losing ground in syria and iraq, so today the Islamic Terrorist Group proved it can still unleash murder and chaos on a large scale. Car bombs went off in three baghdad neighborhoods, killing nearly 100 and wounding more than 160. Isis is from the sunni branch of islam. The bombs targeted mostly shiites, including those living in the sprawling shiite slum known as sadr city. Charlie dagata is there. Reporter the first bomb ripped through a crowded marketplace in sadr city when it was at its busiest this morn morning and when it was certain to kill as many people as possible. A young man could be heard shouting, thats my dad. Thats my dad. Witnesses said a pickup truck piled high with fruit and vegetables blew up outside a beauty salon. Among the victims were brides tobe getting ready for their wedding. Residents were still searching for survivors when isis claimed responsibility for the attack hours later another suicide bomber hit a second shiite neighborhood, this time at a Police Checkpoint. By late afternoon, as the death toll neared 100, there was another explosion. This is where a third suicide bomber blew himself up, targeting a Police Checkpoint in western baghdad. Theyre still washing down the street. This is a residential neighborhood, and there is a sense that nowhere in the capital is safe. Especially as this is a sunni neighborhood, some of whom are loyal to isis. It made no difference to residents here that the intended target appears to have been Iraq Security forces. Police officer mohammed amid told us, i saw bodies on the ground, and i tried to help, but they all died. [gunfire] iraqi forces have been fighting isis for more than two years with help from american air strikes. And while isis has been forced to retreat in recent months, todays events show the militants can still strike with lethal force in the heart of the capital. Weve seen in the past, scott, that when isis suffers significant losses on the battlefield, they launch spectacular attacks in baghdad. Its not the only reason the city is on edge. Demonstrations are already under way in sadr city, and theres a risk theyll spread to other parts of the capital. Pelley Charlie Dagata for us tonight on another bloody day in baghdad. Thanks, charlie. And one more note on isis. The f. B. I. Director james comey said today theres been a steep drop in the number of americans attempting to join the group in the middle east. Two years ago he said it was as many as ten a month. Now it averages one a month. Tonight theres a threat of flash floods, hail and tornadoes from texas to illinois. A tornado plowed through mayfield, kentucky, yesterday, injuring nearly a dozen people. Jericka duncan is there. Reporter as her neighbors picked up the pieces, Angie Winfrey was in tears. This is all that remains of her home. Its just kind of hard to look. Oh, look at that, look at that, look at that. Reporter randal reed captured this video while working at shelby automotive in mayfield. It didnt look that big from where we were standing. Until it crossed the road right here, we had no idea how dangerous it was. Holy mackerel. There it goes. Reporter the twister packed winds of up to 140mph. The funnel cloud would span more than four football fields wide. It destroyed virtually everything in its path for 17 miles. I was really thinking i wasnt going to make it. Reporter Marty Winfrey saw the tornado coming, ran from his home and held on to a tree for survival. I seen that tree, and i thought, thats the only chance im going to have. Reporter his wife angie was at work during the storm. It can all be replaced. It can all be replaced. Its just hard to see it. Reporter the space littered with sipsder blocks is where the doublewide trailer used to be, but the tornadoforce winds carried that home into the neighbors house and even twisted this Steel Foundation around this tree several times. Cleanup efforts are under way, but people here in mayfield say it could take weeks before mounds of debris are gone. The National WeatherService Reports that at least one vehicle was thrown 150 yards from where it was parked. Scott, the last time this region experienced a tornado like this was in 2013. Sadly, three people died. Pelley jericka duncan, thank you. Well, it looked like a tornado devastated the city of west in texas three years ago. Today investigators said that the explosion that leveled part of that town and killed 15 people was deliberate. The blast in a fertilizer warehouse registered as a 2. 1 magnitude earthquake. Manuel bojorquez is on this story. [explosion] reporter the massive explosion was first described as a tragic industrial accident, but the fire that ignited it was today labeled anything but. Oh, my god. Reporter robert elder is with the bureau of alcohol, tobacco and firearms. The fire has been ruled as incendiary. This means this fire was a criminal act. Reporter the april 2013 fire at the west Fertilizer Company caused the chemical Ammonium Nitrate to explode. Since then investigators said they conducted more than 400 interviews. Extensive analysis of the scene and lab work, which included evidence that was found as far as two and a half miles away. They did not name any suspects. The explosion killed 15 people, 12 of them first responders, including phil calvins son perry. I want them to get the maximum penalty. Id like to see them put back in prison so they dont ever see the light of day, whoever it was. Reporter im standing where the blast happened. The 93footlong crater it left behind has been filled, but west is still rebuilding after half the homes here were damaged or destroyed. Scott, the disaster also called into question federal oversight of facilities which store dangerous chemicals in populated areas. Pelley Manuel Bojorquez there for us tonight. Manuel, thank you. Well, in campaign 2016, the highestranking republican in the country today called for unity on the eve of his meeting with the man who has cleaved the party in two. Heres Major Garrett. We need a real unification of our party. Look, after a tough primary, thats going to take some effort. Reporter House Speaker paul ryan said an alliance with presumptive nominee donald trump cannot and will not be rushed. Look, this is a big tent party. There is plenty of room for different policy disputes in this party. Reporter trump today sounded optimistic about the path ahead. I have a lot of respect for paul ryan. If we make a deal, that would be great. And if we dont, we will trudge forward like ive been doing and winning all the time. Reporter at their meeting tomorrow at Republican Party headquarters, ryan will be looking for assurances trump is a true conservative. Today the speaker sat down with House Republicans already backing trump, among them duncan hunter. Were going to meet. Were going to talk. Were going to get to know each other. Were going to tell each other what the priorities are and hopefully have a nice hug after that. Reporter trump also reopened the question about releasing his tax return, telling the Associated Press it would not happen before the election and there was nothing to learn. That prompted this attack from democrat hillary clinton. My husband and i have released 33 years of tax returns. So you got ask yourself why doesnt he want to release them . Yeah, well, were going to find out. Reporter late today trump tweeted he would release his returns before the election, provided ongoing audits were complete. 2012 republican nominee mitt romney, already a harsh trump critic, says its disqualifying for a candidate not to release tax returns. Scott, on Facebook Romney wrote, there is only one logical explanation for mr. Trumps refusal to release his returns there is a bomb shell in them. Pelley Major Garrett in the newsroom, major, thanks. Today federal civil rights charges were filed against former South CarolinaPolice OfficerMichael Slager in the shooting of an unarmed black motorist, walter scott. A trial on state murder charges is set for this fall. Slager could get life without parole. It was the Police Shooting of a black man in ferguson, missouri, in 2014 that ignited the National Debate over policing and racism. Well, this week ferguson swore in a new police chief who sat down with our jeff pegues. So help me god. Reporter when delrish moss was sworn in as the new police chief, he was blunting. If you do the job in a way that disrespects the badge that you hold, ill see to it that youre either removed from Police Service or further prosecuted. Reporter moss, a 32year veteran of miamis police department, has experience with troubled agencies. He was a teenager in miami during the violent 1980s when he says he was harassed by police. He was a white Police Officer. He told me, you n word, dont walk downtown after dark. Another experience not long after that, a Police Officer stops his car, pushes me up against the wall and starts to frisk me. Reporter why would that draw you to lawrmt rather than push it away . My grandmother has a saying, you cant clean a house if youre not in it. Reporter a Justice Department report found in ferguson between 2012 and 2013, every person taken into custody for resisting arrest after a traffic stop was african american. The culture. Reporter fred watt isnts case was in the d. O. J. Report. Four years ago he was sitting in his parked car when a ferguson Police Officer demanded his i. D. I reached to get it from the back in my pocket. He said, put your hands on the wheel, and he pulled out his gun, telling me to get out of the car. Reporter with his gun pointed at your head . Yes. Reporter watsons case is still not resolved. Moss says he will hold his officers to a higher standard. Do you expect to clean house . Oh, i expect to clean house where i find that people need to go. Reporter but moss knows a new police chief is just one step toward real change. Jeff pegues, cbs news, ferguson, missouri. Pelley tonight we have new information about a doctor in minneapolis who treated prince in the final weeks of his life. Jamie yuccas is following the investigation. Reporter prince Rogers Nelson was being treated by minnesota doctor Michael Schulenberg for an undisclosed illness, and now Law Enforcement want to know if it had anything to do with how the singer died. In a search warrant executed last week and obtained by the l. A. Times, investigators seized all medical records, documents, prescriptions and medical images related to prince from schulenbergs North Memorial Medical Center office. The document paints a picture of man in need of serious medical attention the last three weeks of his life. According to the warrant, schulenberg first saw prince on april 7th, the same day prince canceled two atlanta concerts due to an illness. The day after the rescheduled performances on april 15th, princes plane made an emergency stop. Prince had to be treated at a hospital. A week later on april 20th, schulenberg saw prince again, this time giving him a prescription. Its not known what medication schulenberg prescribed, but he told authorities it could be filled at a local pharmacy. The next day, thursday april 21st, schulenberg went to paisley park to deliver Prince Medical test results. He came upon a death scene instead. And he wasnt the only doctor prince reached out to in those final days. Lawyer william muazy represents dr. Howard kornfeld, renowned Addiction Treatment specialist who said princes representatives reached out to him the day before he died. Dr. Kornfeld felt that his mission was a lifesaving mission. Reporter dr. Schulenberg is no longer employled at the medical center. A spokesperson would not tell us why or how he left. And, scott, according to the warrant, princes estate manager says the singer dealt with Health Issues for at least a year. Pelley jamie yuccas covering the investigation. Jamie, thanks. A new study about folic acid in pregnancy gets a reality check from our dr. Jon lapook. And how do you tell more than 900 stories on 60 minutes . Brilliantly and one at a time when the cbs evening news continues. Ivand im doing just fine. Allergies. Claritin provides 24hour relief of symptoms that can be triggered by over 200 allergens. Yeah, over 200 allergens with claritin my allergies dont come between me and victory. Live claritin clear. I smbut ended up nowhere. A lot now i use this. The nicoderm cq patch with unique extended release Technology Helps prevent the urge to smoke all day. I want this time to be my last time. Thats why i choose nicoderm cq. What knee pain . . What sore elbow . Advil liquigels make pain a distant memory nothing works faster stronger or longer what pain . Advil. Wopen up a lot of dawn. Tough on grease. Yet gentle. Dawn helps open. Something even bigger. Go to facebook. Com, dawn saves wildlife. Unless you have allergies. Flonase is the first and only nasal spray approved to relieve both itchy, watery eyes and congestion. No other nasal allergy spray can say that. Go ahead, embrace those beautiful moments. Flonase changes everything. Pelley a medical headline caught our attention today. It suggested a possible link between high levels of folic acid in pregnant women and an increased risk of their children developing an autism spectrum disorder. Well, our dr. Jon lapook has been looking into this and is with us now with a dose of reality. Jon, pregnant women are told to take folic acid. Reporter right. That stays exactly the same. Theres no doubt that women who have too little intake of folic acid during pregnancy have an increased risk of having kids with severe neurological problems, birth defects. So that recommendation from the government, which is to take 400 to 800 micrograms of folic acid a day during pregnancy stays exactly the same. Nobody is questioning that. Pelley so what do you make of this study . Reporter well, this study, normally we would not cover a story that was this preliminary. Its an abstract, meaning it hasnt yet been even submitted for publication to a journal. It has not been reviewed yet by the scientific community. There are some numbers in there that give me pause. For example, the rate of autism that they report is about five times what the c. D. C. Reports. That makes me wonder, are they overdiagnosing autism . That said, what it showed was that women who have very high levels of folic acid, which is folate, or b12 soon after delivery had kids who went on to develop autism at a higher rate than normal. Now, this does not mean that taking too much b12 or folate causes autism. This is an association. There needs to be a lot more study. The bottom line here is the recommendation stays exactly the same. We do not want women to misinterpret this headline. They should still be taking folic acid is uptation during pregnancy. Pelley so despite the headlines weve seen today, this study is extremely preliminary and doesnt change the advice the take folic acid when pregnant . Reporter yes. And, of course, always check with your doctor during pregnancy or any other time when youre taking any kind of is uptation is up mentation or medication. Pelley jon lapook, thank you, jon. Coming up next, the owner could only watch helplessly as firefighters tried to save his house. When a moment turns romantic why pause to take a pill . Or stop to find a bathroom . Cialis for daily use is approved to treat both erectile dysfunction and the urinary symptoms of bph, like needing to go frequently, day or night. Tell your doctor about all your medical conditions and medicines, and ask if your heart is healthy enough for sex. Do not take cialis if you take nitrates for chest pain, or adempas for pulmonary hypertension, as it may cause an unsafe drop in blood pressure. Do not drink alcohol in excess. Side effects may include headache, upset stomach, delayed backache or muscle ache. To avoid longterm injury, get medical help right away for an erection lasting more than four hours. If you have any sudden decrease or loss in hearing or vision, or any symptoms of an allergic reaction, stop taking cialis and get medical help right away. Ask your doctor about cialis and a 200 savings card. When agerelated macular have degeneration, amd we came up with a plan to help reduce my risk of progression. And everywhere i look. Im reminded to stick to my plan. Including Preservision Areds 2. My doctor said Preservision Areds 2 has the exact nutrient formula that the National Eye Institute recommends to help reduce the risk of progression of moderate to advanced amd. After 15 years of clinical studies. Preservision areds 2. Because my eyes are everything. I was in the military for 18 years. M brian. But i smoked. And i got heart disease. My tip is, its hard to serve your country when youre too weak to put on your uniform. announcer you can quit. For free help, call 1800quitnow. Its my job and its i takealso my passion. Rises. But with my back pain i couldnt sleep. So i couldnt get up in time. Then i found aleve pm. Aleve pm is the only one to combine a safe sleep aid plus the 12hour strength of aleve. For pain relief that can last into the morning. And now. Im back. Aleve pm for a better am. Pelley a homeowners Security Camera captured the moment when the canadian wildfire known as the beast came knocking. Firefighters worked frantically to beat down the f