Tens of thousands of Argentines marched through the rain in front of the presidential palace on Sunday to demand answers in the case of a young protester who went missing two months ago.

Opposition and human rights groups believe state security forces took Santiago Maldonado, a 28-year-old craftsman, and allege President Mauricio Macri¡¯s government is covering up information on his whereabouts.

Maldonado was last seen during an Aug. 1 operation by the National Gendarmerie to end a land occupation in Chubut province by the indigenous Mapuche.

¡°My intuition tells me the Gendarmerie have him. Where, I don¡¯t know,¡± Maldonado¡¯s brother, Sergio Maldonado, told reporters at the rally in downtown Buenos Aires.

Protesters marched carrying images of Maldonado¡¯s bearded face and signs that read ¡°may he appear alive now.¡±

Potential cases of abuse by security forces are sensitive in Argentina, where the 1976-1983 military dictatorship secretly detained, tortured and killed people in clandestine prisons. Rights groups say up to 30,000 people were ¡°disappeared.¡±

Macri¡¯s government has said that there is no evidence that shows security forces detained Maldonado.