A prominent Pakistani anti-drone campaigner and journalist whose son and brother were killed by drones was abducted February 5th by over a dozen men, just before he was set to travel to Europe to testify to lawmakers about the war crimes wrought by U.S. drone strikes. He is currently missing, according to his family.

“Kareem Khan is not only a victim, but an important voice for all other civilians killed and injured by US drone strikes,” said Shahzad Akbar, lawyer for Kareem Khan, and Director of legal charity the Foundation for Fundamental Rights.

Kareem Khan lost his 35-year-old brother, Asif Iqbal, a teacher, and his 18 year-old son Zaneullah Khan, who had just graduated high school and was a staffer at a government school and construction worker, when a U.S. drone struck his home in Machikhel, a village in North Waziristan, on December 31, 2009. The third man who died in the attack was a stonemason who had come to town to work on the village mosque.

Khan stated in a previous interview with CNN, “When my house was attacked, it flashed on the news that militants have been killed. There were no militants in my house, neither on the day of drone strike nor before. My house wasn’t a training center, either. Only innocent people where killed.”

Khan is currently in the midst of legal proceedings against the Pakistani government for its failure to investigate the deaths of his family members, which he charges constitute murder under Pakistani law, according to the UK-based charity Reprieve. A hearing before the Islamabad High Court had been scheduled for Tuesday.

Khan was also scheduled to meet with German, Dutch and British parliamentarians later this week to testify on his personal experience and journalistic reporting of U.S. drone strikes.