Merchan, a long-time anti-corruption advocate, had said he feared for his life while defending former road infrastructure director Luis Fernando Andrade who has fled the country, according to Caracol Radio.
Newspaper El Tiempo reported that neighbors hadn’t heard or seen their neighbor since Christmas day.
Merchan’s suspicious death comes less than two months after the death of key witness Jorge Enrique Pizano and his son. Three days after his father, Pizano’s son died of cyanide poisoning.
The cause of Merchan’s death is being investigated by the Medical Examiner’s Office, whose director was forced to resign last week for failing to properly investigate the key witness’ death.
A special prosecutor is investigating the bribery scandal after the Supreme Court removed Martinez and the entire prosecution from the case because of the chief prosecutor’s involvement in the scandal.
Audio released by media after Pizano’s death indicated that Martinez knew about Odebrecht’s bribery practices a year before he became chief prosecutor.
Merchan had been called to testify in the defense of former road infrastructure chief Luis Fernando Andrade, who fled the country after being briefly jailed by Martinez’ office.
Odebrecht allegedly began bribing politicians in Colombia in 2009 and continued its corrupt practices until 2014, according to the United States Department of Justice.
During that period, the Brazilian engineering firm teamed up with a daughter company of Grupo Aval, a banking giant controlled by Colombia’s richest man and Martinez’ former boss, Luis Carlos Sarmiento.
Merchan learned about the alleged bribery from Andrade when working for Santos between 2010 and 2014.