The wife of an Iranian-Canadian environmental activist who died in prison in Tehran last month was barred from leaving Iran, one of her sons said, in an unexplained move that drew an angry response from Canada.

Raam Emami said in an email to journalists that security forces had not allowed his mother, Maryam Mombeini, to get on a plane to Vancouver with him and his brother on Wednesday night.

Mombeini is the widow of Kavous Seyed-Emami, an environmental activist and sociology professor who was arrested on Jan. 24 and died in prison. Iran's judiciary claimed Seyed-Emami, 63, had committed suicide.