The diplomat says Ezzat Atallah, who suffered from diabetes and heart ailments, likely died of natural causes. He spoke anonymously Sunday in line with regulations.
Atallah was among five Evangelical Christian Egyptians detained in Libya for allegedly proselytizing in the predominantly Muslim nation.
Last week, Egypt's Foreign Ministry intervened to win release from Libya of 55 Egyptians who were also suspected of proselytizing. Thirty-five of them were deported for illegally entering the country, while 20 were cleared to stay in Libya.
Also, four foreigners under investigation for alleged espionage and proselytizing remain in a Libyan prison. They are a Swedish-American, a South Korean, a South African and an Egyptian.
