Human rights groups are urging Equatorial Guinea officials to investigate what they call the possible "enforced disappearance" of a top human rights lawyer.
Fabian Nsue Nguema disappeared on Monday after he entered the notorious Black Beach prison in the capital, Malabo, to visit a client.
In a statement Wednesday, Human Rights Watch calls Nsue's disappearance a "grave concern" and urges the government to immediately clarify his whereabouts.
A rights group focused specifically on Equatorial Guinea, EG Justice, says multiple sources report the lawyer has been detained by government security forces and that his car remains parked outside the prison.
Human rights groups have long considered Equatorial Guinea one of Africa's most repressive governments.
Activists say President Teodoro Obiang Nguema rules the country with an iron fist while enriching himself and his associates.
EG Justice says Nsue has served as legal counsel for members of the opposition, and has been the target of government harassment in the past.