Police in Brazil believe that Greece's ambassador to the country was killed by his wife's lover under her orders in a house in the Rio area and have detained three suspects.
Ambassador Kyriakos Amiridis went missing on Monday in Nova Iguacu, a city just north of Rio de Janeiro, where the ambassador had been vacationing.
The couple lived most of the time in the capital of Brasilia.
On Friday, police investigator Evaristo Pontes Magalhaes said that 29-year-old police officer Sergio Gomes Moreira Filho had confessed to killing Amiridis, alleging self-defence.
He said the policeman was having an affair with the ambassador's 40-year-old wife, Francoise.
Filho's cousin, Eduardo de Melo, acknowledged taking part in the killing as a lookout, Magalhaes said.
The cousin accused Francoise of offering him the equivalent of $US25,000 ($A34,655) to participate.
A judge ordered the detention of Francoise, her lover and his cousin, and the three were in custody.
Francoise has denied any role in the alleged plot.
According to Magalhaes, Francoise said she couldn't stop Filho from killing her husband and insisted she was not at home at the time of the crime.
But the police investigator said in a press conference late Friday that the "evidence clearly puts the ambassador's wife as a co-author of the crime."
He said she started plotting with her lover to kill the ambassador after the couple had a serious fight three days before Christmas.
"All our evidence suggests that her motivation was to use the financial resources left by the ambassador so she could enjoy life with Sergio," the police officer, Magalhaes said.
The first signs the ambassador had been murdered emerged late Thursday, when police found blood spots believed to be his on a sofa inside the house the couple kept in Nova Iguacu, where the wife's family lives.
Filho told police that he strangled the ambassador during a fight, but the blood evidence found on the scene makes his claim unlikely, Magalhaes said.
Neighbours said they did not hear any shots, leading police to believe the policeman stabbed Amiridis.
The investigation showed that Amiridis' body was removed from the house in a carpet at the same time that Francoise arrived with their 10 year-old daughter, who did not see the body of her dead father, Magalhaes said.
Police believe a body found in a burned-out car that Amiridis had rented on December 21 belongs to the ambassador, but forensics experts are still working to confirm that it is him.
Brazil's government has offered its condolences to Greece over his death.
The Greek Embassy website in Brazil says Amiridis started his career as diplomat in 1985 in Athens and became Greece's top diplomat in Brazil in 2016.
He earlier was Greece's ambassador to Libya and worked as consul in Rio from 2001-2004.
