The family of an American hostage killed in a US drone strike gave his Al Qaeda captors money in a failed bid to guarantee his release, a report suggests. It has also been claimed Dr Warren Weinstein, from Rockville, Maryland, and a fellow aid worker were used as a shield to protect a senior Al Qaeda operative while in captivity. The 73-year-old was killed alongside Giovanni Lo Porto during an anti-terrorist strike on the Afghanistan-Pakistan border intended to kill members of the group. His family yesterday slammed their response to his abduction, and it has now been claimed that they transferred an undisclosed amount of money to his kidnappers two years before his death. A source in Pakistan who was in regular contact with the captors told CNN that after the money exchanged hands, they started demanding the release of prominent Afghan prisoners. They included the 'poster girl' for jihad Dr. Aafia Siddiqui - who is currently serving an 86-year prison sentence in the United States for the attempted murder of a United States Army captain. Sources suggest the family of American hostage Dr Warren Weinstein, who was killed during a US drone strike in January, gave money to his kidnappers. His wife Elaine (right) has already slammed the US government's response to his abduction . After the money allegedly changed hands, the captors are said to have demanded the release of prominent Afghan prisoners, including the 'poster girl' for jihad Dr. Aafia Siddiqui - who is currently serving an 86-year prison sentence in the United States . He said they were professional during the transactions and they connected themselves to other abductions - including that of murdered journalist James Foley. The source told CNN the militants would call him on a daily basis and when he last spoke to them in early April, they said Weinstein was still alive. However they did not provide a proof of life. When they stopped calling, CNN's source could not contact them as he had no phone number for the captors. He did not reveal how much money had been handed over. According to CBS News' David Martin, Dr Weinstein and Mr Lo Porto may have been used to safeguard an Al Qaeda leader while they were in the compound. US officials have not revealed a specific individual that was targeted during the attacks, but said the compound was hit because intelligence strongly suggested militants were inside. The senior member of the terrorist organisation may have believed if opposition forces knew hostages were in the compound, he would be safe from drone strikes. It has also been claimed that Dr Weinstein (left) and  fellow captive Giovanni Lo Porto (right) were used to shield a senior Al Qaeda operative from drone strikes . The leader being shielded was Ahmed Farouq, a longtime al Qaeda operative who once hatched a plot to hijack Pakistani vessels and ram them into American warships, the station reported. President Obama has taken 'full responsibility' for the attack which killed Dr Weinstein and Italian aid worker Mr Lo Porto in January. Weinstein's wife Elaine has said the US government's reaction to his plight following his capture in Lahore, Pakistan, in 2011 was 'inconsistent and disappointing'. In a statement released on Thursday, she said her family were devastated by the news he will never return home. She said: 'On behalf of myself, our two daughters, our son-in-law, and two grandchildren, we are devastated by this news and the knowledge that my husband will never safely return home. Pictured next to his wife are his two daughters, his son-in-law and two granddaughters . 'We were so hopeful that those in the U.S. and Pakistani governments with the power to take action and secure his release would have done everything possible to do so and there are no words to do justice to the disappointment and heartbreak we are going through. We do not yet fully understand all of the facts surrounding Warren's death but we do understand that the U.S. government will be conducting an independent investigation of the circumstances. 'We look forward to the results of that investigation. But those who took Warren captive over three years ago bear ultimate responsibility. I can assure you that he would still be alive and well if they had allowed him to return home after his time abroad working to help the people of Pakistan. 'The cowardly actions of those who took Warren captive and ultimately to the place and time of his death are not in keeping with Islam and they will have to face their God to answer for their actions,' Mrs. Weinstein said. 'Warren spent his entire life working to benefit people across the globe and loved the work that he did to make people's lives better. In Pakistan, where he was working before he was abducted, he loved and respected the Pakistani people and their culture. He learned to speak Urdu and did everything he could to show his utmost and profound respect for the region. 'We cannot even begin to express the pain our family is going through and we ask for the respect of our privacy as we go through this devastating ordeal.' 'I want to thank Congressman John Delaney, Senator Barbara Mikulski, and Senator Ben Cardin - as well as specific officials from the Federal Bureau of Investigation - for their relentless efforts to free my husband. 'Unfortunately, the assistance we received from other elements of the U.S. Government was inconsistent and disappointing over the course of three and a half years. We hope that my husband's death and the others who have faced similar tragedies in recent months will finally prompt the U.S. Government to take its responsibilities seriously and establish a coordinated and consistent approach to supporting hostages and their families.' 'I am disappointed in the government and military in Pakistan. Warren's safe return should have been a priority for them based on his contributions to their country, but they failed to take action earlier in his captivity when opportunity presented itself, instead treating Warren's captivity as more of an annoyance than a priority. I hope the nature of our future relationship with Pakistan is reflective of how they prioritize situations such as these.' During a press conference on Thursday, President Obama  revealed two other Americans, both prominent members of the terrorist organization, were killed in during missions in the same region. Ahmed Farouq, an American who was an Al Qaeda leader, was killed in the same January operation that resulted in the hostages' deaths while notorious hate preacher and US-native Adam Gadahn was killed in a separate US mission. The commander-in-chief gave his 'deepest apologies' to the families and revealed he had spoken to Weinstein's wife and the Italian Prime Minister Matteo Renzi on Wednesday. President Obama has taken 'full responsibility' for the attack which killed Dr Warren Weinstein, admitting that US forces sometimes make 'deadly mistakes' Defending the operation, he said it was 'fully consistent' with guidelines set out for counter-terrorist missions. 'As a husband and as a father, I cannot begin to imagine the anguish that the Weinstein and Lo Porto families are enduring today,' Obama told reporters, with a deep sigh. 'I profoundly regret what happened,' Obama said, explaining he declassified some of the details of the operation so that the families could know what happened.' 'There could be no starker contrast between these two men and their captors.' He added there will be a full review into the deadly incident and his press secretary, Josh Earnest, later said both of the victims will be given compensation by the US government. Earnest did not reveal how much they would receive, but the figure could be in the millions.
Dr Warren Weinstein died during the counterterrorism operation in January . The 73-year-old was captured from his home in Lahore, Pakistan, in 2011 . His family are said to have transferred money to his kidnappers in 2012 . They asked for the release of prominent Afghan prisoners in return . The transaction did not lead to his release and his family have since slammed the US government for their 'disappointing' reaction . US officials insist the family will be receiving compensation for his death .