Karim Khan, who was missing since February 5, was released early on Friday after being abducted from his home by some men in police uniforms.

A statement by the legal charity Reprieve, which is working with his lawyer Shahzad Akbar, said Mr. Khan was taken to a cell in an undisclosed location.

Later in the day, on February 5, he was blindfolded and driven for approximately 2 to 3 hours to another undisclosed location where he remained until his release. During his detention, Reprieve said, Mr. Khan was interrogated, beaten and tortured. He was chained and repeatedly questioned about his investigations into drone strikes, his knowledge of drone strike victims and his advocacy work.

Early on Friday morning, he was driven to the Tarnol area of Rawalpindi, where he was thrown out from a van after being told not to speak to the media. Mr. Akbar had filed habeas corpus proceedings in the Rawalpindi bench of the Lahore High Court which ordered the Ministry of Interior to ask the intelligence services to produce Mr. Khan by February 20.

Reprieve said Mr. Khan plans to go ahead with his trip to meet parliamentarians in the U.K., Germany and the Netherlands later this week. He was quoted as saying that when he was picked up, he thought he would never see his family again and that he would never be freed going by all the stories he had heard about disappeared people. He thanked activists and lawyers who had helped secure his release.

Mr. Khan, whose son and brother were killed in a drone strike, was going to leave on Saturday to Europe to speak about the drone strikes to members of European parliaments. He had also filed a court case demanding action for the drone strikes.

Mr. Akbar said in the statement, “What happened to Khan in the last few days is nothing new in Pakistan …We need to take this stand for each and every person who disappears, it is the only way to force those in power to listen.”

Reprieve legal director Kat Craig said: “It is a huge relief that Mr. Khan has finally been released …Serious questions remain for the Pakistani Government on how this was allowed to happen.”