Murdered Greek ambassador's wife arrested in connection with the crime

Her police officer lover confesses to killing the diplomat

Greek ambassador Kyriakos Amiridis had been missing since Monday night (AP)

The wife of Greece's ambassador to Brazil has been arrested on suspicion of her husband's murder.

Kyriakos Amiridis's burned corpse was was found in a torched car under a motorway underpass in Rio de Janeiro.

He had rented the vehicle with his Brazilian wife Francoise, who reported him missing to police on Wednesday, following his disappearance on Monday. The couple have a 10-year-old daughter together.

Investigators arrested her in connection with the killing, after a fellow officer – who is thought to be her lover – confessed to the killing, according to a local TV news station that cited police sources.

Sergio Moreira, 29, admitted to murder shortly after Mr Amiridis's disappearance Globo TV reported.

Investigators told the station they believed his wife and Mr Moreira had arranged the murder in advance.

Both Mr Amiridis' wife and the officer were in custody, but it was not clear if they were being advised by lawyers.

Police and Rio state security officials declined to comment on the Globo report and their investigation.

Francoise Amiridis, the wife of Greece's Ambassador to Brazil Kyriakos Amiridis, arrives at a police station to be interrogated in connection with her husband's disappearance in Belford Roxo (AP ) (AP)

The Greek embassy in Brasilia declined to comment and in Athens, Greek foreign ministry spokesman Stratos Efthymiou said the government had no comment.

Mr Amiridis served as Greece's consul general in Rio from 2001 to 2004. He was Greece's ambassador to Libya from 2012 until he took the top Brazil post at the beginning of 2016.

Two other suspects have also been detained in connection with the crime but they were not identified.

A burned corpse was found inside a car parked under a motorway overpass (Reuters)

Blood was also reportedly found on a couch inside the home, according to local media reports and Globo TV showed footage of police carrying a sofa into police headquarters.

The incident is another blow to Rio's image, just four months after it hosted the Summer Olympics.

The neighbourhood where the car was found is dominated by powerful and politically connected armed groups comprised mostly of off-duty or retired police and firefighters who control vast areas.

They often extort residents in exchange for keeping drug gangs from taking over the areas.

The armed groups have grown for several years and often curry favour with local politicians by promising to deliver votes from entire neighbourhoods as long as authorities allow them to carry out their crimes.

Crime in Rio has been rising and the state is deeply indebted, often unable to pay police and other salaries on time, if at all.