(CNN) -- A Michigan congressman said Sunday that relatives are trying to blackmail him with decades-old allegations that he sexually abused a young cousin, an accusation he called "false and shameful."
Rep. Dale Kildee, a Democrat who has held his Flint-area district since 1976, said he once went to the FBI after one relative threatened to go public with the claims if he didn't get federal benefits for the cousin, now an adult with a history of mental illness.
Kildee, 82, announced in July that he would retire at the end of his current term. His nephew Dan Kildee is running for the seat.
Family members recounted the claims -- which Kildee said date back 50 years -- in audio recordings posted online and published by The Washington Times.
"Republicans tried to peddle these scurrilous allegations during my last congressional race and authorities and reputable news outlets rejected these false allegations," Kildee said in a statement issued Sunday night. "Now they are back at it again to try to win an open congressional seat."
Attempts to contact the congressman's office were unsuccessful Sunday night. But in video posted on the Washington Times' website, Kildee said there's "no shred of truth" to the accusation.
"I'm going to respond and let people judge," he added.
The Washington Times reported the interview was conducted by Jon Yinger, a Michigan religious broadcaster. In it, one of Kildee's relatives said she is coming forward because the man "will never speak for himself."
"I am doing what I prayed he could do, but he's not," she says.
But the woman also says the man's wife once called Kildee's office to try to get federal benefits for her husband.
"She was blackballing, or blackmailing, Dale with this information, so it wasn't a comfortable situation," the relative recounts during the interview. "She basically went to him and said, 'You're going to get me his Social Security disability or I'm going to go public with that.' "
Kildee highlighted that portion of the recording in his press release, saying it had occurred 20 years ago. He also released a copy of what he said was the last letter he had received from the cousin, in 1988, in which the man asks for Kildee's help in establishing a "global telethon" to end hunger in Africa. The letter is signed, "With all my love."