At least 21 officers returned fire. Nearly 400 rounds riddle the suv. Multiple shots fired we need a bearcat. We need medical aid. Right now we have one down outside the car. One down inside the car. Reporter Rizwan Farook gets out, but he doesnt get far, his body lying in a pool of blood just across the street. Malik, her 6monthold daughter at home with grandma, dies in the vehicle. As darkness falls, a robot enters the shooters home. Found inside thousands of rounds of ammunition, 12 pipe bomb, and what investigators call a bomb lab. With hundreds of tools that could be used to make explosives. And the question remains tonight with all of those bombaking materials, the pipe bombs, the tools found in the couples home, did they have bigger plans . Were there other targets . That we may never know. But the fbi digging through their garage, their home today to try to find any clues they can as to what could have possibly been the motivation behind this mass murder. Poppy harlow, cnn, San Bernardino, california. The fbi has also been interviewing the gunmens family as they try and piece together a possible motive for the shootings, even farooks brotherinlaw said he had no idea why farook and malik carried out the attack. As tom foreman shows us, thats just one of the questions facing investigators right now. Lets start at this Office Gathering where Authorities Say farook left angry after some sort of dispute and returned in short order with his wife and the shooting began. Thats where the first real question arises here. And that is what set him off. Was it really an honest dispute or was it some sort of pretext to start the attack . Were there any warning signs . Was he having any problem that somebody might have been aware of that would have told him this was on the way . And why were the explosives not detonated . Authorities tell us they had some bombs of a short here that could have been set off remotely. They were never set off. Did they get out of range . Did they forget . Did they change their mind . We dont know. Move to their home about a six minute drive away, and we get a whole new set of questions. The first one being why did they return home . Certainly farook had to be aware of the possibility that someone at the office would have recognized him and alerted police. And indeed the police were there. They spotted them. The chase followed. The shootout as well. Beyond that, when you think about all of the thousands of rounds of ammunition, all the bomb making equipment authorities have cited in the home, how long were they preparing . Thats another important question. And beyond that, if you move to the final stage here, the shootout in which they lost their lives here, there is a big question in play here. Were they planning Something Else, either before or after this other event here . Why did they act now . And was someone else involved, either on the ground or from afar helping them out . These are all the many, many, many questions that are out there right now, and there arent so far many answers. Thanks to tom foreman for that. And of course, isha, amid all of the chaos and the carnage here, because this attack was at a county function and involved county workers at a government facility, many of the government buildings around San Bernardino were put on lockdown. And that included the hospitals as well. As they ferried all of the wounded to the hospitals, the doctors inside were treating them in a lockdown situation, not entirely sure what was happening. Because at this point, at the height of all of this, the gunmen were actually still out there, both farook and his wife malik. Hospitals have drills for this kind of thing. But i dont think anything request truly prepare you for the minute you realize you have victims of mass shooting heading your way. 21 people were wounded in this brutal mass shooting, and they were rushed to the nearby hospitals. Six patients were taken to arrowhead Regional Medical center. And the doctors and nurses had just minutes to prepare. This picture was taken in the hospitals trauma room wednesday, just before the victims arrived. Cnns chief medical correspondent dr. Sanjay gupta spoke to some of the medical team about what they faced that horrific day. Youre look inside one of the Emergency Rooms where patients were brought after the mass shooting that rocked Southern California. We have ten operating rooms ready to go. And radiology was ready. Everyone was ready. So here is where things took place. Were in the emergency room, the Arrowhead Medical center. Here is where the calls came in. At about 30 minutes before the patients would start to arrive. Behind these doors are the trauma bays. Take a look at what it looks like now and compare it to what it looked like yesterday. For every patient brought in, there are four or five doctors prepared to treat the wounded. If youre looking at one of these bays, what does it look like as youre waiting for the stations to come in . Essentially, we had a senior er resident at the head with attending anesthesiologist. We had an attending trauma surgeon at the foot running the show. And we had a junior er resident doing primary survey, disrobing patients and checking for injuries. Reporter dr. Kona singh was the er doctor in charge. How much information do you have before the patients actually come to the doors . Very little, to be honest. Essentially, i was given reports of patient injuries as far as location, where they were shot. And mental status. That was basically all we had as they hit our doors. We had to sort of prepare for a larger influx of patients than we normally would. Things you wouldnt normally think of, calling blood bank for blood, getting enough blankets, enough iv fluids. Reporter dr. Detective is the chief of surgery, who along with dr. Seng spoke exclusively to cnn, describing how they had to manage the worst mass shooting these doctors had ever seen. We made a decision to send one patient straight to the operation room, two patients to the ct scan and one had to wait. Its the waiting, the not knowing. Thats the toughest part for any medical team. What is the thing you worry about the most in these types of situations . That your resources get stretched so much that you might not be able to provide care to all the people. Who come. And you have to decide who goes first, who goes second, who goes third. Sometimes you have to decide who is who is futile so dont waste a lot of time and resources. And that can be the most difficult thing you can decide in mass casualties. Thats something you probably think about over and over again. Absolutely. Because in my mind, god should be the one who decides that rather than you. Reporter whoever made the decision, all six patients treated here are expect to survive. And do well. Dr. Sanjay gupta, cnn, San Bernardino county, california. A horrifying day for those First Responders. Well, for two decades, the u. S. Centers for Disease Control has not been allowed to research gun violence. Ahead well hear from a doctor who said thats a Public Health issue and wants that ban abolished. Believe it. At t and directv are now one. Which means you can watch in the house, in a treehouse, or even in miss pepperpies house. Pause in your pjs and hit play during a pb j. Nice and enjoy some cartoons instead of listening to dads car tunes. dad meet you all the way get the best of both worlds. Directv at home and 2 wireless lines. From directv and at t. Like limiting where you earn bonus cash back. Hings. Why put up with that . But the quicksilver card from capital one likes to keep it simple. Real simple. Im talking easy likea walkinthepark, nothingtoworryabout, manthatfeelsgood simple. Quicksilver earns you unlimited 1. 5 cash back on every purchase, everywhere. 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You are watching cnns breaking coverage of a deadly shooting here in california. Im isha sesay in los angeles. Im john vause in San Bernardino. Authorities here in california believe a combination of workplace grievances and terrorism may have led to wednesdays deadly shooting. Sources say the gunmen syed Rizwan Farook was apparently radicalized. He had been in touch with a number of people under investigation by the fbi for International Terrorism. Meantime, Law EnforcementOfficials Say they have recovered two smashed cell phones from a garbage can near one of the crime scenes. Officials suspect the phones were damaged to try and hide the call history. And authorities recovered a computer from the shooters home. But the hard drive was missing. Investigators believe it was removed and possibly destroyed. Ill have much more from San Bernardino in just a few moments. But in the meantime, lets go back to isha in los angeles with more information about the Mass Shootings in the United States and some more perspective on just how often these events occur. Yeah, john, its important to put this all in context for our viewers, because records show that Mass Shootings occur in the u. S. On average more than once a day. Shooting tracker. Com defines a mass shooting as one that leaves four or more people wounded or dead. There have been 353 of those in the u. S. This year. Taking place in 220 cities and 47 states, including wednesdays attack, a total of 462 people have been killed in Mass Shootings in 2015. And more than 1300 have been injured. Well, in their first appearances since wednesdays shooting, republican president ial candidates expressed condolences to the victims families and survivors. And while president obama has hesitated on calling the shooting terrorism, some gop candidates didnt hold back. We had another event which probably was the one yesterday, probably was related. Radical islamic terrorism. And ill tell you what. We have a president that refuses to use the term. He refuses to say it. There is something going on with him. Politically correct doublespeak that comes from the obama militia. Has again beyond the point of ridiculous. I am convinced that was a terrorist attack. [ applause ] and the president continues to wring his hands and say well see. The brutal savagery of islamic terrorism exists. And that president and his former secretary of state cannot call it for what it is. Thank you so much for joining us. Now, you said the u. S. Is dealing with a gun violence epidemic. And you actually belong to a group of physicians who believe we should be looking at the problem of gun violence as a Public Health issue. Why is that important . Gun violence is something that is affecting communities, individuals, families across the country every single day. And as medical professionals, as doctors, as nurses, as Public Health professionals, were seeing these people coming into our hospital, ers, people coming in with injuries, people who are killed by violence, were seeing them. Were having to treat them every single day. So it is clearly a Public Health issue. So with that in mind, ive got to ask you. What went through your mind when you first heard about wednesdays mass shooting in california . Well, like everyone else, i was had a mixture of shock and a feeling of wow, is this happening again . Yet one more time. And i really have the sense that weve had this ban on the cdc doing Gun Violence Research for 20 years. And it is time. It is beyond time for congress to take action and make sure that we can do research so we can prevent these kind of tragedies from happening so, so often. To talk to me about the impact of this ban. Talk to me about the kind of data you believe is being lost because its in place. Well, we do have a small number of researchers who have been doing research during the past 20 years. But its not nearly enough. We have over 32,000 people who are dying of gun violence every year in america. And there is so much information that we dont have. We dont know what are the best ways that we can prevent a teenager from committing suicide with a gun. Where are the urban violence that is happening, where are those guns coming from. Are they illegal . Are they legal . What are the best ways to prevent a child from accidentally finding a gun and shooting their sibling . These are some basic questions that we need answered. And i think its worth underscoring what you just said. The focus here is not simply looking at Mass Shootings of the kind that just happened in california. Exactly. Youre looking at gun violence as a whole. Absolutely. 89 people a day are dying from gun violence in this country. 2 3 are from suicide. There are so many people who are being harmed, families that are being harmed. And we need answers. How much buyin do you have from Law Enforcement for the lifting of the ban on research . There. Is a lot of there is a lot of outcry among certainly among the medical and Public Health community. I think there are a lot of people in this country who dont even me this ban is in effect. Most people have i talked to, they say what . We cant do research on gun violence . That doesnt make any sense. So the more weve been talking to people, the more people have realized wow, this is a ban that makes no sense for this country. We need to lift it now. We need to fund the research that is going to save lives. How optimistic are you that the ban will be lifted . I am a optimistic. Congress has an opportunity right now to lift the ban. If they dont do it now, they have an opportunity at any moment that i can can lift this ban. And we are seeing an increasing outcry among so many people who are saying this is not an issue of right versus left, of republicans versus democrats. These are questions Everyone Wants answers to. Every time we hear stories of another shooting, one of the first questions all of us ask is how did this happen and how can we prevent it. And that is exactly what were trying to get done. Dr. Chen, we appreciate your efforts. Youre joining us here to discuss them. Thank you so much for speaking us to. Thank you so much for having me. Time for a quick break. A shattered Community Takes a step toward healing. Just ahead, a look at the candlelight vigil to remember those killed in the San Bernardino shooting. Gotta take a sick day tomorrow. Dads dont take sick days, dads take nyquil severe the nighttime, sniffling, sneezing, coughing, aching, fever, best sleep with a cold, medicine. Hucheck out credit karma today. E credit karma, give yourself some your own credit. 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Hundreds gathered for a candlelight vigil at a stadium in San Bernardino on thursday night. Impromptu vigils sprang up near the site of the shooting. Also at churches throughout the area. The largest mosque in San Bernardino county also held a prayer vigil for the victims. Muslim leaders have been quick to condemn the massacre as well. U. S. President barack obama also honored the shooting victims during the annual Tree Lighting ceremony in washington on thursday night. The first family was there for the lighting. And while it is normally a fun, joyous occasion, there were some somber moments as well as mr. Obama took time to honor those who were killed. Their loss is our loss too. For were all one american family. We look out for each other. In good times and in bad. They should know all that all of us care about them this Holiday Season. Theyre in our thoughts. Theyre in our prayers. And we send them our love. 14 People Killed. 21 people who 17 people, rather, who were wounded in the community now left to reel after another shooting tragedy. And of course isha, we have seen these scenes play out so many times before after these kind of Mass Shootings. People come together. They pray. And then they pray and they hope that these things will never happen