B.J. Penn is officially coming out of retirement, but his legal troubles might not be done yet.

The Hilo (Hawaii) Police Department has launched a second-degree sexual assault investigation into the UFC legend stemming from allegations made by the girlfriend of a former employee, sources told MMA Fighting.

The alleged victim filed an incident report in February regarding the matter in Delaware County (Ohio), where she currently lives. Hilo PD public information officer Chris Loos confirmed to MMA Fighting on Monday that the Hilo PD received a hard copy of that incident report last week.

Loos said a second-degree sexual assault investigation has been initiated, but could not comment on the names of any of the parties involved or any details. Sources confirmed with MMA Fighting that Penn is the subject.

The alleged victim wrote in a report filed with the Delaware County Sheriff's office Feb. 16 that she had been sexual assaulted in Hawaii. The report stated that the information would be forward on to the Hilo police. MMA Fighting has chosen to omit the name of the alleged victim.

That same week, Pedro Carrasco, the former editor of Penn's website BJPenn.com, took to Twitter and accused Penn of sexually assaulting his girlfriend.

"Tired of seeing this pervert BJ Penn in the news," Carrasco wrote. "Dude's a cocaine addict, who sexually assaulted my Playboy model gf, and I have proof."

Carrasco added in another tweet: "[Penn] came to my home when I wasn't there and forced himself on my girl, pulled her clothes off, then blamed me, said I looked at his GF ass."

Carrasco has since made his Twitter account private, but the tweets remain.

Penn denied the accusations in a statement on his site in February.

"The allegations that Pedro and his girlfriend are making against BJ Penn simply aren't true," the statement read. "Penn trusted Pedro to run his website for almost a decade and considered him family. He was fired last year for unethical behavior and was provided a severance [sic] that ended on February 16, 2016. One day later allegations appeared in a one sided Twitter rant which happen to be many months after the alleged date in question. (August of 2015). There are many holes in Pedro's story. In the almost 15 years that Penn has been a champion fighter there has not ever been any incident or allegation in regards to his conduct with women. He is family man and father of two young daughters with a known long term girlfriend. It is unfortunate that someone that BJ considered family is trying to extort him."

Last week, UFC president Dana White told Yahoo! Sports writer Kevin Iole that Penn would officially be coming out of retirement to fight Dennis Siver at UFC 199 on June 4 in Los Angeles. The UFC said after the allegations were made in February that Penn's comeback would be put on hold pending an investigation.

In a statement last week, the UFC said that its law firm Campbell & Williams looked into the matter and determined that no action had been taken against Penn by law enforcement, though the UFC reserves the right to reevaluate the situation should new information be made available.

"Following a review of the matter by Campbell & Williams, a Las Vegas-based law firm hired by UFC to evaluate the situation, UFC has been informed that no criminal or civil charges have been filed against Penn to date, nor has any action been taken by local law enforcement. It should be noted that UFC reserves the right to reevaluate the matter should new information be made available," the full UFC statement read.

The UFC did not immediately return a request for comment on this latest development.

On Monday in an appearance on The MMA Hour with Ariel Helwani, Penn would not go into detail about the situation, saying his lawyers would likely not want him to do so. He did address the allegations, however.

"It put me on the backburner for a little while," Penn said. "That definitely hurt my heart. I've got kids, I've got two baby daughters, and of course something like that is going to hurt your heart. People know who I am and what you see is what you get with me. I'm just a family man, I've got two kids, and you know, that's it. I wish I could get into more, but I'm sure my lawyers wouldn't appreciate that.

"I'm just very glad that the UFC did its investigation with an outside company, and I'm just very glad it's done. That's as much as I can say. I'm very glad it's done. I'm very disappointed in how everything happened between me and my former employee. But besides that, I'm very glad that I get a chance to get back in the Octagon."

Penn, 37, is one of the best and most popular fighters in the history of mixed martial arts. He is one of just two men, along with Randy Couture, to hold titles in two different UFC weight classes. Penn (16-10-2) was inducted into the UFC Hall of Fame last year. "The Prodigy" has not fought since a loss to Frankie Edgar in July 2014.