President Barack Obama delivers a statement Thursday, April 23, 2015, apologizing for a U.S. attack in January that accidentally killed two aid workers held hostage by al Qaeda, American Warren Weinstein and Italian Giovanni Lo Porto. Reuters

American citizen Dr. Warren Weinstein was one of two al Qaeda hostages accidentally killed in January by the U.S. government during a counterterrorism operation, the president said Thursday. Weinstein's widow, Elaine, later released a statement about President Barack Obama's acknowledgment of and apology for the killings.

"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," the statement read.

Weinstein, along with Italian hostage Giovanni Lo Porto, was killed in an operation near the Afghan-Pakistan border. The Wall Street Journal first reported Thursday morning that the accidental deaths occurred after the Central Intelligence Agency targeted a drone strike on an al Qaeda compound in Pakistan. The CIA conducted extensive surveillance on the compound but was unaware the hostages were held in the area, according to the Journal.

Weinstein was captured Aug. 13, 2011, by the terrorist group at his home in Lahore, where he was working as an economic development adviser on contract with the U.S. Agency for International Development, according to ABC News.

"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," the statement from Elaine Weinstein read. "In Pakistan, where he was working before he was abducted, he loved and respected the Pakistani people and their culture."

Weinstein, who was then 70 and was reportedly about to leave Pakistan at the time of his kidnapping, was taken by five men who forced their way into his house, overpowering guards before taking him off in a getaway car, the Daily Beast reported.

Weinstein had a house in Rockville, Maryland, where he had lived with Elaine. He spent more than three years in captivity, during which he and his family pleaded for his release. In a 2013 letter -- published by the Washington Post -- written to the media while in captivity, Weinstein described himself as a former college professor at SUNY Oswego, a past Peace Corps volunteer and a consultant interested in human rights. The letter called for action to get his release, asking the media for assistance after his appeals to Obama were unsuccessful.

"I believe that if they negotiate in good faith with my captors I could be released -- hopefully before my time and age end the issue," the letter ended.

The statement from Elaine Weinstein said the family would await the results of an investigation on the facts of Weinstein's death, but also expressed their disappointment.

"We were so hopeful that those in the U.S. and Pakistani governments with the power to take action and secure [Weinstein's] 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," the statement read.

"But those who took Warren captive over three years ago bear ultimate responsibility," the family added. "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."