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LIMA, Feb 24 (Reuters) - Grana y Montero shares fell more than 30 percent on Friday on a report the Peruvian builder knew about $20 million in bribes paid to former President Alejandro Toledo by scandal-tainted Brazilian firm Odebrecht SA.
Hildebrandt en sus trece, a local magazine, said the former head of Odebrecht Peru, Jorge Barata, told a prosecutor the firm's three junior partners on a highway project were aware of an agreement to bribe Toledo for help winning the contracts.
Grana was one of Odebrecht's local partners on two sections of a project to pave a road from the Peruvian Amazon to Brazil. Odebrecht is embroiled in a massive corruption scandal stretching across a dozen countries.
"The rest of the companies did know, not the details, but they did know there was an agreement," the Hildebrandt report quotes Barata as telling prosecutors in the attorney general's office. "They knew we made the payments and knew they would have to assume their part."
Reuters could not immediately confirm the authenticity of published documents that Hildebrandt said represented Barata's official testimony.
Barata, who has agreed to testify in an influence peddling and money laundering case against Toledo, did not immediately respond to requests for comment.
Grana, which previously has denied any knowledge of or involvement in $29 million in bribes that Odebrecht has said it distributed to win contracts in Peru, said on Friday it could not provide an immediate comment.
Peru's attorney general's office declined to comment.
Grana's shares were last trading down more than 33 percent in afternoon trading.
The Peruvian government has barred Odebrecht and any other companies found to have been involved in graft from bidding on public work contracts.
Peruvian prosecutors have previously cited Barata's testimony as key in the decision to charge Toledo, who led the Andean nation from 2001 to 2006. A Peruvian judge issued an international arrest warrant for Toledo two weeks ago.
Toledo, last believed to be in the United States, has denied any wrongdoing and has refused to turn himself in while his lawyer files appeals.
(Reporting by Mitra Taj and Ursula Scollo; Editing by Alden Bentley and Paul Simao)