(Adds details of police raid, political context, quote from lawmaker)
By Anthony Boadle
BRASILIA, Dec 15 (Reuters) - Brazil's lower house of Congress will investigate Speaker Eduardo Cunha for lying about Swiss bank accounts, its ethics committee decided on Tuesday, dealing the second blow of the day to the man who launched impeachment proceedings against President Dilma Rousseff.
Earlier on Tuesday, police raided Cunha's homes as part of a corruption investigation into kickbacks on contracts at state-run oil company Petrobras.
The speaker is fighting for political survival in the face of calls for his resignation and multiple investigations for taking bribes, including a recent accusation that he received 45 million reais ($12 million) from investment bank Grupo BTG Pactual.
The house ethics committee voted 11-9 to begin hearings on whether to strip Cunha of his seat and his political rights for lying to a congressional hearing on corruption in March, when he said he had no bank accounts abroad.
Cunha triggered impeachment proceedings against Rousseff on Dec. 2 over opposition allegations that she violated budget laws to increase spending during her re-election campaign last year.
The ethics case and the police raid may weaken Cunha's effort to unseat the president and undermine his credibility in the divided Brazilian Democratic Movement Party. The PMDB is the largest party in Rousseff's governing coalition, and its moderate members hold crucial swing votes to decide on her impeachment.
Rousseff is struggling to contain the political crisis amid Brazil's worst recession in 25 years and the massive Petrobras graft scandal, but she is not being investigated for corruption.
Prosecutors are investigating whether Cunha, who is third in the line of presidential succession, received a $5 million kickback in the graft scheme uncovered at Petroleo Brasileiro SA , as Petrobras is formally known.
Alerted by Brazilian authorities, Swiss prosecutors located accounts held by Cunha and his wife at the Julius Baer bank and found details of lavish credit card spending.
As evidence mounted against him, Cunha lost control of the lower house, where lawmakers have asked prosecutors to force his ouster.
Committee members almost came to blows on Thursday in a heated argument over attempts by Cunha's supporters to put off a vote against him.
"Any speaker in the same situation, anywhere in the world, would have already quit his post," said Congressman Chico Alencar, from the leftist PSOL party.
$1 = 3.8715 Brazilian reais Reporting by Anthony Boadle; Editing by Lisa Von Ahn