D.C. Council member Vincent B. Orange (D-At large) is warning that his election opponents’ decision to focus on donations he received from city contractor Jeffrey E. Thompson opens the door to a bruising campaign before the Democratic primary on April 3.

D.C. council member Vincent Orange (Sarah L. Voisin/THE WASHINGTON POST)

In an interview with the Washington Post,. Orange said he’s “clean” in the federal investigation into the city’s political culture and predicted it will not hamper his bid for re-election. He said he will soon be highlighting his opponents’ records.

The FBI and IRS raided Thompson’s home and office on Friday as part of what Thompson’s firm called an ongoing “federal investigation into campaign finance in the District of Columbia.”

Thompson owns Chartered Health Plan, which has a $322 million Medicaid contract with the District, the city’s largest. Thompson has contributed to or helped raise hundreds of thousands of dollars for local and federal political candidates over the years, including at least $100,000 to Orange over the past decade, according to a Washington City Paper analysis last year.

In his 2011 campaign for the council, about half of Orange’s money came from people or companies with ties to Thompson, according to a Washington Post review.

On Monday, WAMU reporter Patrick Madden reported that Orange received 26 money orders for $1,000 each within three days last year. WAMU reported it had traced the money orders back to donors who have ties to Thompson or his former spokeswoman, Jeanne Clark Harris.

Federal authorities also searched Harris’ office on Friday. Neither she nor Thompson has been charged with any crime.

Former council member Sekou Biddle and consultant Peter Shapiro, both candidates against Orange in the April 3 primary, are calling on Orange to release the details of the money orders.

“If someone would ask me to verify the authenticity of a contribution to my campaign, I would pull out a copy of the check and show it to them,” Biddle said in an interview. “I wouldn’t want there to be any suspicion.”

Orange has so far declined his opponents’ request, saying the “investigation taking place has nothing to do with Vincent Orange.” Orange said he “simply got Thompson” to host a fundraiser for him and had no reason to suspect the money was coming from a limited number of sources.

“I went to a fundraiser and made my speech,” Orange said. “I have full disclosure. I am in compliance with the law. I am going to move forward with my campaign unless something illegal comes out” from the investigation.

As part of his campaign, Orange said, he’s preparing to place a sharper focus on Biddle’s record.

Orange accuses Biddle of hypocrisy, noting he also accepted donations from corporate donors and limited liability corporations when he served on the council last year.

Biddle was an interim member for four months, before losing to Orange in an April special election. Biddle is now campaigning for his old seat.

“He wants to focus on the last reporting period, but he doesn’t want the focus on himself,” Orange said in the interview.

Orange noted that Lorraine Green, a former advisor to Mayor Vincent C. Gray (D), hosted a fundraiser for Biddle last year. Green is at the center of the investigation into whether Gray campaign officials paid mayoral candidate Sulaimon Brown during the 2010 election campaign.

“He’s a creation of this administration,” Orange said of Biddle.

Orange also cited a $250 donation received by Biddle last year from Ivanhoe Donaldson, a former deputy mayor in Marion Barry’s administration. Donaldson served four years in prison in the 1980s for stealing $190,000 from the District government

Orange also questioned why Biddle worked last year with Quantum Politics, a company that has also done extensive work for Council Chairman Kwame R. Brown (D).

Federal authorities have been investigating how Brown spent campaign funds during his 2008 reelection campaign. Brown endorsed Biddle last year, but is neutral in this year’s contest.

Orange also demanded to know why Biddle knowingly hired a Republican campaign manager who illegally brought a gun into the John A. Wilson Building last year.

Vicky Wilcher, who received one year of probation following the May incident, has since left the Biddle campaign. Wilcher, a West Virginia resident, told the Washington Post last year she forgot to take the gun out of her purse. At the time of the gun incident, she was working for Orange.

Biddle said Orange is merely “trying to deflect” because “there is a cloud hanging over him.”

“He has all these money orders and no answers for them,” Biddle said. ”He should be answering the questions.”

An earlier version of this story inaccurately reported that Harris was Orange’s former spokeswoman. It has been corrected.