The body of Carlos Alexandre Pereira Maria was found on April 8 in a bullet-riddled car in Curumau, east of Rio de Janeiro, local media reported.
Pereira, 37, had been cited to testify in court as part of the investigation of the March 14 assassination of councilwoman and socialist activist Marielle Franco and her driver Anderson Gomes. Franco was a strong opponent of the military take-over of Mare, a poor neighbourhood in Rio home to about 140,000 people.