The Homeland Security Department lied about receiving an angry letter from disgraced former Rep. Randy “Duke” Cunningham recommending a limousine company for federal contracts and then, a day later, released a copy of the letter it claimed it didn’t have.

The latest twist in the tale of Shirlington Limousines _ which is part of a federal investigation into whether a defense contractor provided Cunningham with prostitutes and limos _ prompted ridicule and disbelief from lawmakers.

A department spokesman said the letter was discovered in a folder by an administrative assistant who had read news reports Friday morning about its disappearance.

“She says, ‘Oh, I get those kinds of letters all the time, I just throw them in a folder,” said DHS spokesman Larry Orluskie. “So she starts looking through the folders and finds this letter.”

Lawmakers said the reappearance of the letter prompts additional questions.

Homeland Security Committee Chairman Peter King, R-N.Y., said, “Despite repeated assurances to the contrary, it now turns out that the department had the Cunningham letter all along.”

“This letter certainly puts the department’s credibility on the line, and raises further questions about political manipulation in the contracting process,” said Rep. Mike Rogers, R-Ala.

“If we can’t trust them to find a letter, how can we trust them to find a terrorist?” asked Rep. Bennie Thompson, D-Miss., the Homeland Security Committee’s top Democrat.

Rogers chaired a Homeland Security subcommittee hearing Thursday looking into why Shirlington received two Homeland Security contracts worth about $25 million despite a history of problems.

The letter, dated Jan. 16, 2004, is a character reference by Cunningham, a California Republican now serving prison time for bribery, on behalf of Shirlington President Christopher Baker, whose rap sheet included prosecutions for petty larceny and robbery.

“I have personally known Mr. Baker since the mid-1990s. He is completely dedicated to his work and has been of service to me and other members of Congress over the years,” Cunningham wrote.

“Mr. Baker’s transportation-oriented business was able to withstand the devastating impact of 9/11, while operating from Hangar 7 at Ronald Reagan International Airport. Please be advised of my full support of his wish to provide transportation services for the Department of Homeland Security.”

Four months later Shirlington got its first contract from the Homeland Security Department, for $4 million.

Orluskie said Cunningham’s intervention had nothing to do with the awarding of the contract.

In fact, his letter was found in a folder labeled “Motor Pool” in the administrative department and apparently never made it to the procurement division, Orluskie said, which is why searches for it were unsuccessful.

Questioned about the letter on Thursday, department spokesman Ross Knocke had declared, “There was no letter.”

Cunningham’s letter was just one aspect of Shirlington’s contracts that lawmakers are questioning. Shirlington drafted a contract proposal the same month Cunningham sent the letter _ but several months before the contract was actually bid in April 2004. And in an April 20, 2004 e-mail, Shirlington requested an advance on the contract _ even though it wasn’t awarded the contract until seven days later.