Police say they believe Greece's ambassador to Brazil was killed by his wife's lover, a military police officer, under her orders.
Ambassador Kyriakos Amiridis, 59, went missing Monday in a city just north of Rio de Janeiro, where he'd been vacationing.
Friday, 29-year-old police officer Sergio Gomes Moreira Filho confessed to killing Amiridis, but claimed it was self-defense.
The officer claimed he was having an affair with the diplomat's widow, Francoise Amiridis. He also alleged Francoise had started plotting to kill her husband after they had a fight three days before Christmas.
Francoise denied having any role in the alleged plot and said she was not home when the crime occured.
Filho's cousin, Eduardo de Melo, admitted to acting as a lookout during the killing. He told police Francoise offered him $25,000 to do so.
A judge ordered that all three be detained.
"All our evidence suggests that her motivation was to use the financial resources left by the ambassador so she could enjoy life with Sergio," a police investigator said.
Amiridis' body was found in a burned car in Nova Iguacu. Police said they believe the officer and his cousin killed the ambassador in his home then wrapped his body in carpet and put it inside a rental car before setting it on fire.
Amiridis started his career as a diplomat in 1985 and became Greece's top diplomat in Brazil in 2016.
The Associated Press contributed to this report.