Brazilian police have arrested Mario Marcelo Santoro over the death of his former girlfriend Cecilia Haddad, whose body was found in Sydney’s Lane Cove River.

The Rio de Janeiro police department said Santoro was arrested at a relative’s home in the city’s Botafogo district on Saturday.

Local footage shows Santoro being led through a frenzied media pack on his way into a police station.

He was arrested a day after police searched his home in Rio de Janeiro as well as the homes of his parents and relatives. A warrant for his arrest was issued on Thursday.

Santoro flew back to his native Brazil on the same late April weekend the 38-year-old Brazilian mining executive’s fully-clothed body was found in the Lane Cove River.

NSW homicide detectives are preparing to travel to Brazil “as soon as international protocols have been met”, said a police spokeswoman.



“NSW Police Force is continuing to work through commonwealth processes in order to bring a successful conclusion to their investigation.”

Fabio Cardoso, from Rio’s homicide division, said police believe Haddad was killed by asphyxiation.

“In April, by not accepting the break-up, he [ Santoro] allegedly killed her by asphyxiation by pressing her neck and dumping her body in the river,” Cardoso told the Seven Network in Brazil.

“We know he had the key to her house because he lived there for a while.”

NSW police issued a warrant for the 40-year-old’s arrest last month but there are concerns Santoro will never be extradited to Australia to face charges because of Brazilian laws and customs.

Foreign minister Julie Bishop last week told reporters Australian authorities were “working closely” with Brazilian counterparts to ensure an “appropriate” outcome.

A spokesman for attorney general Christian Porter said on Sunday the government did not comment on extradition matters, including whether an extradition request had been made or if it intended to make one.

“This is a matter for Brazilian authorities,” he said.

“We understand from media reporting that the arrest is pursuant to a domestic Brazilian charge for the murder which is alleged to have occurred in Australia, however we are working closely with NSW authorities and INTERPOL to confirm the basis for the arrest.”