U. S. Intelligence says the terrorist was a highranking terrorist, and they did not know two hostages were with them. 73yearold Warren Weinstein, an aid worker from maryland, had been kidnapped nearly four years ago. Giovanni loporto of italy, who worked for a humanitarian agency, had been held since 2012. We also learned today that two more americans were killed, but both of them were members of al qaeda. In an unexpected announcement the president called it a tragedy. I take full responsibility for all our Counterterrorism Operations including the one that inadvertently took the lives of warren and giovani. I profoundly regret what happened. On behalf of the United States government, i offer or deepest apologies to the families. Pelley the president went on to say it was a cruel and bitter truth that deadly mistakes happen in the fog of war. David martin has learned what went wrong. Reporter the drone strike happened in january, but it wasnt until april that the c. I. A. Realized it had killed the two hostages. American aid worker Warren Weinstein and italian giovanni loporto. All the safeguards president obama once promised would ensure to a near certainty no innocent civilians would be killed had failed. Based on the intelligence that we had obtained at the time, including hundreds of hours of surveillance, we believed that this was an al qaeda compound, that no civilians were present, and that capturing these terrorists was not possible. Those hundreds of hours never detected any sign of the hostages. But intelligence analysts did see evidence of a senior al qaeda operative. Exactly who they did not know. That seemed to make it even more unlikely hostages were in the compound since there were no previous cases in which hostages had been held close to al qaeda leaders. It now appears the hostages were kept nearby as shields for the Senior Leader who turned out to be an american named ahmed farouk who once hatched a plot to hijack pakistani vessels and ram them into american warships. Five days later another drone strike killed another american, again without the c. I. A. Knowing it. This time it was adam gadahn who played a leading role in al qaeda recruiting and pop gann that video. Gadahn had been indicted for treason and had a 1 million reward on his head. Neither gadahn or farouk were considered senior enough to be on the c. I. A. s hit list, but when asked if the president regretted killing them, white house spokesman josh earnest had a very simple answer. No, those two individuals you mentioned were lead centers al qaeda. Reporter the c. I. A. s Inspector General has been ordered to investigate what went wrong, and members of the Senate IntelligenceCommittee Say they will conduct an investigation of their own. Scott . Pelley david martin at the peg for us tonight. David, thank you. Were told it took four months to make todays announcement because of the difficulty of getting reliable evidence from hostile territory. The president broke the news himself to Warren Weinsteins widow in a phone call. The u. S. Government says it will pay compensation to his family and loportos. Wyatt andrews has more on weinsteins ordeal and his familys reaction. Im regretting this video to president obama. Reporter in this video released by his captors 16 months ago, Warren Weinstein asked the president to negotiate his release. I am also appealing to you as someone who has served his country and who now needs his country to help him. Reporter weinstein was a career foreign aid worker who went to back assistant in 2004 as a Government Contractor advising pakistani businesses. He was kidnapped in a daring raid by al qaeda operatives who tricked his guards into opening the front gate of his compound. This was just days before he was due to leave pakistan. In the maryland neighborhood where he and his wife raise two daughters, there is a yellow rib been on every tree. One of the neighbors is meredith mccain. I cant express how sad we feel and how much sympathy we have for mrs. Weinstein and her daughters. Reporter in a statement mr. Weinstein says his captors bear ultimate responsibility, but they also fault the pakistani government for not finding weinstein treating warrens captivity as more of an annoyance than a priority. The family also questions why help from some elements of the u. S. Government was inconsistent and disappointing. Last year weinsteins wife elaine publicly complained when her husband was not part of the deal exchanging one army soldier, Bowe Bergdahl for five taliban captives. It would have been nice if they traded five prisoners for five hostages. Reporter so far the weinstein family is not questioning the drone strike itself, but, scott it is asking why in the case of a Government Contractor the state department and Intelligence Community could not track down where weinstein was. Pelley Wyatt Andrews at the weinstein residence. Thank you very much, wyatt. Adam gadahn, one of the american terrorists killed, was familiar to many. Ben tracy has his story. We have sufficient justification to continue the fight and kill americans. Reporter on dozens of internet videos, adam gadahn threatened attacks on major u. S. Cities called 9 11 payback for American Crime and encouraged muslims in the west to kill americans. A single word of american protest shall be silenced by a thousand islamic bombs. Reporter the videos first surfaced in 2004 landing gadahn on the f. B. I. s most wanted terrorists. In 2006, he became the First American indicted for treason since the world war ii era. Former f. B. I. Agent Errol Southers says gadahns Language Skills are what made him valuable. He really resonated with that englishspeaking audience that al qaeda was trying to attract and he had the savvy and cachet to know arabic, so he was somewhat authentic and had street cred, if you will. Reporter gadahn grew up in a farm and converted to islam when he was 17. He became increasingly radical and was kicked out of the center in 1997 after hitting the imam Imam Haitham Bundakji in the face. I think he had some family problems. Reporter shortly after that gadahn left the country and joined al qaeda. His father philip seemed dumbfounded when he talked to cbs news in 2004. I didnt imagine hes involved in anything like what theyre thinking he might be. Reporter there has been no sign of gadahns family at their national in Southern California today, but scott a relative who lives in los angeles just found out today hes been killed, and she learned that from the media, not the u. S. Government. Pelley ben thanks very much. Now, lets bring in cbs news contributor Michael Morell who is the former number two at the c. I. A. Morell is still bound by laws of secrecy, so there are aspects of this that he cannot talk about. Michael, let me ask you about these two americans who were members of al qaeda. First ahmed farouk, why did he matter . Scott he was a senior al qaeda operative. He was involved in external operations. He was involved in terrorist planning in western europe and the United States. He was a very significant player to remove from the battlefield. Reporter . Pelley the world is a safer place without it . No doubt about it, scott. Pelley adam gadahn, the other american . Adam is a longtime propagandist. It was his job the radicalize individuals overseas. It was his job to sell the al qaeda message. Pelley after what weve learned today, do the risks of these strikes outweigh the benefits . Scott, i dont think so. The Collateral Damage is very low. These are the most precise weapons in our arsenal. And, scott these strikes theres no doubt in my mind that these strikes, which have been fairly aggressive since 2008 have prevented another 9 11style attack in the United States. Pelley Michael Morell, former Deputy Director of the c. I. A. , thank you very much. Youre welcome. Pelley and we have breaking news tonight in baltimore. Police are clashing with protesters there who are angry over the mysterious death of a man who died in police custody. Chip reid is there. Chip . Reporter well, scott earlier this evening hundreds of protesters in this park surged into the streets to walk the three miles from here to the part of baltimore where the incident occurred and where the Police Station is based. Along the way, they came across a police presence. They surrounded a police van. There was a series of scuffles. At least two were taken into custody. Other protesters threw objects at the police. Apparently it was a fairly ugly situation. But after a couple were taken into custody, the people continued along their way. And a short time ago they arrived at the Police Station. Scott . Pelley chip reid in baltimore where there have been scuffles with police over the death of man who died in police custody. Chip, thank you very much. This may have been the single toughest day for the jury deciding whether to execute the Boston Marathon bomber. The prosecution wanted its last day to be unforgettable, and don dahler is there. Reporter this is the image prosecutors hope will stay in the jurors minds as they consider the Death PenaltyDzhokhar Tsarnaev lurking behind a tree just feet away from his youngest victim. Moments later ] explosion] eightyearold Martin Richards body was torn apart bay bomb blast. Dr. King told the boy the boy would have been in extreme pain. I can say with an extraordinarily high degree of medical certainty that he did not die instantaneously. Earlier the jurors were shown a series of photos of victims, a virtual parade of prosthetic limbs. They saw xrays of fucarile fiewks ravaged body. His leg had been blown off dozens of bbs and other shrapnel perp rated every part of him. Heather abbott took the stand next, i was catapulted into the restaurant and i landed on the ground in a puddle of chaos and blood and glass. We first met abbott ten days after the blast. She talked about the agonizing moment herer is john told her she would need to amputate her leg. I certainly didnt want to, but to be told i couldnt do things i wanted to do. Hopefully im going to be around a while. Reporter then it was steve woolfendens turn. He is seen struggling to check on his injured threeyearold son leo in his stroller. Woolfenden watched helplessly as his son called mommy, daddy mommy, daddy, was carried away in the arms of a policeman. The prosecution ended her case with the image of Denise Richard comforting her dying son martin. In the video the boy was still moving. Scott, i can tell you that there werent just tears in the courtroom. In the overflow room, many journalists were also overtaken by emotion. Pelley don, thank you very much. The defense will begin their presentation next week. Today the Senate Finally confirmed Loretta Lynch to succeed eric holder as attorney general. Five months after she was nominated. The vote was 5643. Only ten republicans voted yes. Many who voted no based their opposition on lynchs defense of the president s executive actions on immigration reform. Former c. I. A. Director David Petraeus was sentenced to two years probation today and fined 100,000 for giving classified information to his mistress. Petraeus was considered americas most successful general. He turned the tide in iraq, but he fell for a woman writing his biography and gave her access to his secret email. His sentence is interesting because our Research Department tells us similar offenses by lowerranking offenders often result in prison time. 13 months and 20 months in two recent cases. A funeral was held in malta today for 24 immigrants who died trying to make it from north africa to europe. Their bodies were the only ones recovered from sundays disaster off of libya that killed nearly 900. It is up to italys coast guard to rescue these men and women stranded while attempting the perilous voyage. And Clarissa Ward spent time with the guard while on assignment for 60 minutes. Reporter the Italian Coast Guard has now started to dread good weather. A flat blue sea can spell disaster, triggering a flood of refugees to attempt the crossing at once. We have never seen Something Like this. Reporter captain Leopoldo Manna is the man who received those desperate Satellite Phone calls from migrants abandoned by smugglers at sea. His Coast Guard Command Center in rome works around the clock, knowing that if their boats dont take action, the migrants will likely die. Difficult to explain that sometimes we have 25 boats asking for rescue. We dont know exactly where they are, and they all ask to be rescued. You cant rescue all of them. Its not possible to rescue 25 altogether and you dont know where they are. Reporter do they understand the risk . I believe they understand the risk. Reporter but it doesnt stop them . I believe they are so determined that nothing will stop them. Reporter so its like these smugglers are putting a gun to your head. Something like that. They put a gun in front of us to save these people, almost Something Like that. Pelley you can see clarissas remarkable report sunday night on 60 minutes. Theres a whole lot of shaking going on. Scientists reveal whats behind the sharp increase in earthquakes. And a volcano awakens from a 40year nap when the cbs evening news continues. 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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 for daily use and a free 30tablet trial. Pelley government scientists said today that man is to blame for a surge of earthquakes. Oklahoma has now surpassed california in seismic activity. Manuel bojorquez is on shaky ground. Were having another earthquake. Reporter this is some of the shaking in oklahoma where since 2009 there have been 300 times more earthquakes than in previous decades. The house was shaking violently. Reporter sandra ladra showed us last month the damage she still has from the largest quake there. Could you believe this was an earthquake happening . It was hard to because i had never been in anything like that. Reporter a portion of oklahoma is now one of 17 regions identified by the u. S. Geological survey for humancaused earthquake activity, possibly triggered by oil and gas production. Waste water from fracking operations is typically injected deep underground and that could reactivate dormant falls. In oklahoma, scientists announced this week they believe the majority of recent earthquakes in some areas were likely triggered by those types of disposal wells. And while mostly minor, the quakes are happening in areas where homes are not designed to earthquake building codes. Matthew hornbach and brian stump are scientists at Southern Methodist university who studied a swarm of earthquakes near azle, texas. They say their Research Shows activity that natural gas wells have gone from a possible cause to the most likely. You can never say with 100 certainty. But the pressures caused by oil and gas activity at the right depth, the right location and the right time to provide the most stresses to cause earthquakes. Reporter but the scientists also point out the majority of wells are not associated with earthquakes. Scott, the oil and gas industry says it supports further research i