(Adds comment from Lobao's lawyer, father being investigated)
By Lisandra Paraguassu
BRASILIA, Feb 16 (Reuters) - Brazilian police targeted the son of Senator Edison Lobão and a former senator in search-and-seizure operations on Thursday, a source said, investigating possible bribes paid during construction of the Belo Monte hydroelectric dam.
Federal police said they were searching homes and offices based on warrants issued by a Supreme Court judge handling a sweeping corruption probe known as "Car Wash," but did not disclose the names of the targets who were members of two political parties.
But a source with knowledge of the matter said the targets included a former senator, Luiz Otavio Campos, and Marcio Lobão, whose father is a senator and was energy minister in the government of impeached leftist and former president, Dilma Rousseff.
Campos and Senator Lobão are affiliated with the ruling Brazilian Democratic Movement Party.
The warrants were issued by Justice Edson Fachin, police said in a statement, based on evidence obtained during the Car Wash probe, Brazil's largest corruption investigation.
Lawyers for Marcio Lobão, who is chief executive officer of the Banco do Brasil's investment wing Brasilcap, said he had committed no illegal act. In a statement, they called the warrants "drastic."
The two face possible charges of corruption, money laundering and involvement in a criminal organization, based on evidence suggesting they were involved in political bribes paid by some builders of the massive Belo Monte dam in the Amazon rainforest, police said.
The senior Lobão was recently elected chairman of the Senate Constitution and Justice Committee, which confirms nominees for the Supreme Court.
While the senator was part of the ousted Workers Party government, he is a leader of President Michel Temer's PMDB party, and Thursday's police operation will not help efforts to distance the president's administration from the corruption scandal.
Lobão and four other PMDB senators are being investigated for allegedly taking bribes from an engineering consortium that won the Belo Monte contract when he was the minister responsible for the state electricity companies that own the dam.
The 26 billion reais ($8.5 billion) Belo Monte project started generating electricity last year and could become the world's third-largest hydroelectric dam when all its turbines come on stream by 2020. ($1 = 3.051 reais) (Writing by Silvio Cascione and Anthony Boadle; Editing by Gareth Jones, Bernadette Baum and Jeffrey Benkoe)