Delvonn Heckard, 46, filed a lawsuit against Murray this month under the pseudonym "D.H."
In the lawsuit, he said the mayor "repeatedly raped" him when he was a 15-year-old boy and the mayor was 32 at the time. Heckard said Murray also paid him for sexual acts.
Heckard's attorney, Lincoln Beauregard, sent a letter to Murray's attorney this week revealing his client's full name.
"I can state categorically that I have never had a sexual relationship with this individual Delvonn Heckard, of any kind or at any time," Murray responded in a statement made through his spokesman Jeff Reading. He added, "I just learned Heckard's name this morning and can say that his name is not familiar to me."
The complaint also alleges that Heckard was not the only child abused by the mayor. "On at least one occasion, D.H. was at Mr. Murray's home when another apparently under aged boy was at the apartment. D.H. was of the understanding that Mr. Murray was having sex with the other boy for money at the same time," the complaint reads.
Reading said the allegations are completely unfounded.
"These false accusations are intended to damage a prominent elected official who has been a defender of vulnerable populations for decades," he said.
"It is not a coincidence that this shakedown effort comes within weeks of the campaign filing deadline. These unsubstantiated assertions, dating back three decades, are categorically false. Mayor Murray has never engaged in an inappropriate relationship with any minor."
Reading added that the mayor will "vigorously fight these allegations in court."
Details of mayor's anatomy in dispute
In the complaint, Heckard described Murray's scrotum as having a "unique mole" in the shape of a "small bump."
But Murray's personal physician found "no mole or bump," the mayor's attorney Robert Sulkin told reporters this month.
A few days later, Murray spoke out about the accusations.
"To be on the receiving end of such untrue allegations is very painful for me," the mayor said. "It is painful for my husband and for those who are close to us. I understand the individual making these allegations is troubled, and that makes me sad as well."
The accusations come at a critical time for Murray: He's on the cusp of a mayoral election in Seattle. But this isn't the first time allegations of sexual misconduct have surfaced during a crucial point in his political career.
In 2008, while Murray was promoting his marriage equality campaign, The Seattle Times
reported that two men accused Murray of "molesting and raping" them in the '1980s and tried to start a smear campaign with media organizations.
Sulkin said the accusers in the 2008 allegations "were aligned with a virulent anti-gay organization" and that the claims were "found to be false by law enforcement."
The allegations are from events that took place more than 30 years ago, so why come up with these accusations now? According to the complaint, Heckard felt empowered to move forward with the allegations against Murray because of the recent passing of his father. He hopes to attain "accountability" from Murray who in his eyes, "maintains a position of authority" and ultimately "give courage for other potential victims to come forward and speak out."