LONDON — A prominent British-Iranian scholar detained in Iran since April has returned to Britain, according to an advocacy organization he helped found.

The scholar, Abbas Edalat, a professor of computer science and mathematics at Imperial College London, was taken into custody by the Islamic Revolutionary Guards Corps on April 15 while in Tehran to visit family and attend an academic workshop. He is a founder of the Campaign Against Sanctions and Military Intervention in Iran.

The group said in a statement on Saturday that Mr. Edalat had come home earlier in the week. It did not specify the reasons for his detention or release but suggested that the Iranian authorities had concluded they may have erred in holding him.

“It increasingly appears, as we had suspected, that his detention in spring in Iran was a case of misinformation and misunderstanding by the Iranian security apparatus,” the group said.