The victims, a retired married couple from Savonlinna, were selling their winter home on the Brazilian coast when they and a friend were killed.
The police found the suspect in São Paulo after having been given a tip-off as to the man’s whereabouts.
According to the media, the 58-year-old mechanic was found in a flat on the northern side of the metropolis on Wednesday.
Head of the investigation Rodolfo Santa Cruz confirms to Helsingin Sanomat that the man has been apprehended.
A number of credit cards belonging to the murdered Finns were found in his possession.
The arrested man was a prospective buyer of the Finnish couple’s house, and the motive of the killings apparently involves financial problems linked with the sale of the house.
The police interrogated the mechanic soon after the discovery of the bodies, but he nevertheless managed to leave for São Paulo, which is located more than 2,000 kilometres away from João Pessoa.
The police have already earlier arrested a 51-year-old man who is suspected of helping the mechanic commit the crimes.
According to the head of the investigation, the police have no other suspects.
The mortal remains of the deceased Finns are still in Brazil, but preparations are being made to bring the bodies back to Finland.
Jari Luoto, the Finnish Ambassador to Brazil, says that a date for the transportation has not been set yet. The paperwork for the move has not been completed.
”The arrangements are under way”, Luoto reports.
Markus Talvio, the lawyer representing the victims’ families, says that once the deceased are in Finland, a new forensic examination will be performed on them.