SAO PAULO (Reuters) - Brazilian federal police said they had served two detention orders and executed 16 search and seizure orders on Thursday as part of a new phase of a corruption probe into the state oil company Petrobras.

The new phase concerns dealings between building firms and executives at the oil giant known formally as Petróleo Brasileiro SA, according to a police statement.

Prosecutors said the targets were businessman Adir Assad and lawyer Rodrigo Tacla Duran, who were accused of helping to launder money for the homebuilders involved in the scheme. Neither man is a current or former Petrobras employee. Assad has been under arrest since March.

A lawyer for Assad was not immediately available for comment. Efforts to contact Duran’s lawyer were unsuccessful.

The prosecutors they suspected Duran of laundering “tens of millions” of reais for the firms UTC Engenharia and Mendes Júnior Trading Engenharia, which were then funneled into bribes.

“Investigations uncovered evidence that the operators used sophisticated money-laundering mechanisms, including bank accounts in the name of offshore companies abroad, front companies and fake contracts,” prosecutors said.

Police and prosecutors were due to offer more details in a press conference at 10 a.m. (8.00 a.m. ET).