LAS VEGAS (KLAS) — A Las Vegas law firm accepted paperwork on behalf of Nick Carter, signaling it is representing him against allegations he raped a teenage girl, court records revealed Thursday.

An attorney with Hayes Wakayama Juan accepted service of the complaint against Carter, a member of the Backstreet Boys, on Jan. 3, records showed. The attorney nor the law firm returned a request for comment Thursday.

The lawsuit, filed in Clark County last month, alleges Carter also raped three other victims between 2003 and 2006, including a 15-year-old girl.

Shannon “Shay” Ruth claimed in her lawsuit that she was 17 years old when Carter, who was 21 at the time, gave her alcohol, raped her, and threatened her if she told anyone, documents said.

In February of 2001, Ruth was invited onto a tour bus in Tacoma, Washington by Carter while she was waiting in line for an autograph. On the bus, Carter gave her cranberry juice with alcohol and said it was “VIP juice” after Ruth told him the drink tasted weird, according to the lawsuit.

After Ruth drank the juice, the lawsuit said, Carter took her to the bathroom of the tour bus and assaulted her. He became irritated when Ruth got upset, asking her “Why are you crying?! Stop crying,” according to the lawsuit.

Carter then took Ruth to the back of the tour bus and raped her, the lawsuit said.

ABC pulled a Backstreet Boys holiday special when the allegations were made public in December.

Singer Nick Carter attends the premiere of Gravitas Ventures’ “Backstreet Boys: Show ‘Em What You’re Made Of” on Jan. 29, 2015, in Hollywood. (Alberto E. Rodriguez/Getty Images)

Ruth did not report the incident because of his threats, according to the lawsuit. It was later discovered that Carter infected her with human papillomavirus, or HPV, the lawsuit said.

Around 2003, another victim, who was not named, said Carter gave her alcohol and raped her. She later tested positive for HPV, according to the lawsuit.

In December, Carter’s attorney Michael Holtz denied the allegations in a statement obtained by Variety.

“This claim about an incident that supposedly took place more than 20 years ago is not only legally meritless but also entirely untrue,” the statement read. “Unfortunately, for several years now, Ms. Ruth has been manipulated into making false allegations about Nick — and those allegations have changed repeatedly and materially over time.”

AJ McLean, Kevin Richardson, Brian Littrell, Nick Carter, Howie Dorough
AJ McLean, from left, Kevin Richardson, Brian Littrell, Nick Carter, and Howie Dorough of The Backstreet Boys appear at the 61st annual Grammy Awards in Los Angeles on Feb. 10, 2019. (Photo by Jordan Strauss/Invision/AP, File)

Carter was also accused of rape by singer Melissa Schuman, who claimed he raped her in 2003. The statute of limitations expired before charges could be filed, and Carter has denied that allegation.

Ruth and Schuman were named because they chose to identify themselves as victims of sexual assault. Victims of sexual assault are not named unless they choose to publicly come forward.

No court date in the civil lawsuit was scheduled as of Thursday.