When armed gunmen stormed the Lahore home of Warren Weinstein, 73, the American aid worker and professor that had spent decades working in the developing world was just two days away from heading home.

Almost four years later and President Barack Obama announced that Weinstein had been killed in a drone strike somewhere in the lawless border region between Pakistan and Afghanistan, along with fellow hostage and Italian Giovanni Lo Porto.

The father of two and grandfather was a professor at State University of New York at Oswego and lived in Maryland before moving to Lahore to take on a US-funded project for development firm J.E. Austin Associates. He was supervising an $11m US-funded development project that advised Pakistani businesses and the government across a range of development sectors.

Weinstein was seized from his home in Model Town, Lahore, in 2011 by an Al Qaeda gang that distracted his security guard and burst into his house through a rear window. They kidnapped Weinstein, three of his guards and a driver at gunpoint.

Al Qaeda leader Ayman al-Zawahiri claimed that he was personally holding Weinstein and said that he would be released if the US stopped its air strikes in Afghanistan, Pakistan, Somalia and Yemen. Zawahiri also demanded the release of Al Qaeda and Taliban prisoners.

Over the years, Al Qaeda produced a number of proof-of-life videos as well as appeals to the US and President Barack Obama from Weinstein himself via the group's media arm, Al Sahab.

In May 2012, he appeared in a video warning that he would be killed if Obama did not agree to the group's demands. Weinstein appealed in another video aimed at Israeli Prime Minister Benjamin Netanyahu, arguing that Obama and the US government had shown no interest in his case and appealing to him for help: "as one Jew to another".

In a statement issued by the Weinstein family on April 23, his family pointed to his work to help the people of Pakistan. They pointed to his desire to understand other cultures, which included learing fluent Urdu as well as five other languages.

He had also served with the peace corps in Togo and the Ivory Coast, spent seven years at USAID and the World Bank.

"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," the statement said.