Mohammadi died at Tehran's Evin prison on July 30, several days after starting a hunger strike. The circumstances of his death are unclear.
The Iranian-based Defenders Of Human Rights Center says the death is suspicious and has called for an independent probe.
Mohammadi was one of the leaders of the 1999 student protests that triggered Iran's biggest domestic crisis since the Islamic Revolution two decades earlier.
He was initially sentenced to death for his role in the unrest. The sentence was subsequently commuted to 15 years in prison.
FOCUS ON YOUTH: Kaveh Basmenji is the head of RFE/RL's Persian-language Radio Farda. He was born in Tehran in 1961 and began working as a journalist at the age of 16. He recently spoke with RFE/RL correspondent Golnaz Esfandiari about his book "Tehran Blues" (Read an excerpt from the book.) and the role of youth in Iranian society today... (more).