BEIRUT (AP) — A Palestinian-Syrian software pioneer has been executed in prison after being arrested five years ago by Syrian authorities in Damascus, his widow and colleagues said Wednesday, in what Amnesty International said was a "grim reminder of Syrian prison horrors."

Noura Ghazi Safadi wrote on Facebook late Tuesday that she has received confirmation that security services executed Bassel Khartabil in October 2015 after torturing him in prison.

Khartabil, who also went by the name Bassel Safadi, was a champion and leading contributor to Arabic Creative Commons, a framework for coding an...