In the final scheduled forum for the 6th District congressional race Thursday, Republican candidates turned on Garret Graves, who has raised the most money, sharply questioning him about who contributed to his campaign and how his father’s firm won government contracts while he was a member of the Jindal administration.

Paul Dietzel, of Baton Rouge, first brought up support Graves received from an environmental group that has spent nearly $2 million opposing GOP candidates in other states.

State Sen. Dan Claitor, of Baton Rouge, then questioned how an engineering firm run by John Graves, the candidate’s father, procured so many government contracts.

Claitor said he found Evans-Graves Engineering, of Baton Rouge, and New Orleans was awarded about $132 million in government contracts during the five years Graves was Gov. Bobby Jindal’s chief adviser on coastal affairs and chairman of Coastal Protection and Restoration Authority.

Graves responded that he was glad to finally get a chance to answer that question, which has been percolating behind the scenes for several months. He said he had nothing to do with any of the contracts Evans-Graves won.

“As a senator, if you thought that was the situation, what was happening, you should be calling the FBI, the State Police, not bringing it up right here,” Graves said, his anger rising.

Graves repeated what he said was the number of his father’s contracts in which he played a role: “Zero.” He then slammed down the microphone with an audible thunk.

It was former Gov. Edwin W. Edwards, the Democrat in the race, who came to Graves’s defense.

“I’ve known this man’s father for a long, long time. He’s an honorable man and a great engineer. And since we needed the engineering work here, so be it. At least somebody from Louisiana got the money, not necessarily someone from out of state like our present governor likes to award contracts,” Edwards said to laughter.

The state Division of Administration listed six contracts between the state and Evans-Graves, worth a total of $676,162. Only one was let during Graves’ tenure, and that was approved by the Recovery School District in June 2009 to renovate a play yard at Sylvanie Williams Elementary School in New Orleans.

The U.S. Army Corps of Engineers, which is a federal agency, granted about $130 million worth of contracts for coastal and levee projects.

The Coastal Protection and Restoration Authority works closely with the Army Corps, but Graves didn’t sign engineering and construction contracts.

Graves, who took a job in his father’s firm when he left the Jindal administration earlier this year, said the Army made its own decisions that did not involve him. “I did not get involved in contracting decisions and always shielded the folks who made those decisions from the politicians that tried to influence the process,” Graves said after the forum.

However, many of the initial supporters of Graves’s well-funded campaign are linked to subcontractors who do work for Evans-Graves.

Graves collected more than $1.1 million and spent about half that, mostly on fliers and televisions commercials that have blanketed the Baton Rouge market through Sept. 30, according to his latest campaign reports

That amount is almost as much as the next three best-funded candidates — Claitor, Dietzel and Edwards — combined, according to the Federal Election Commission documents.

One of those donors is the Environmental Defense Action Fund.

Dietzel pointed out that the political action committee spent about $1.8 million trying to defeat Republican Senate candidates in Iowa, Colorado, Michigan, North Carolina and elsewhere.

The group gave Graves $5,000 and spent another $120,000 on fliers and robo-calls supporting Graves.

He asked why an organization so entrenched in Democratic Party issues would spend money on a conservative, as Graves claims to be.

Graves ticked off contributions to his campaign from the Koch Brothers, the notable financiers of conservative causes, to energy companies such as Occidental and Marathon.

“I think it’s impressive that the work that I did on the coast with the oil and gas industry was attractive to such a diverse group of folks,” Graves said.