A years-old Portland police investigation that surfaced this week has renewed scrutiny of a prominent sports and entertainment figure and set off an unusual review by the NBA into a team owner's conduct.

Mark Cuban, owner of the Dallas Mavericks professional basketball team, is facing questions about his conduct after revelations that police had investigated him in 2011. A woman claimed Cuban had shoved his hand down the back of her jeans and penetrated her vagina with his finger at a downtown Portland nightclub.

Cuban denies it, and he was never arrested. Multnomah County prosecutors reviewed the police evidence and declined to pursue criminal charges, citing a lack of evidence. But the case, first reported by Willamette Week, has revived interest in the alleged incident and prompted a former nightclub employee to come forward.

The headlines have created problems for Cuban, who drew fire last month after a Sports Illustrated investigation described years of sexual misconduct claims in the Mavericks' front office. None of those claims involved Cuban.

The NBA said it is now launching its own review of the 2011 investigation.

It all began when the woman, whose name has not been released, contacted the Portland Police Bureau roughly a week after the alleged incident.

She told investigators she saw Cuban at the Barrel Room on Northwest Third Avenue during the wee hours of April 23, while out with her boyfriend and a female friend, according to a redacted copy of the police report.

[Read the entire 2011 Portland Police Bureau report here]

Cuban, a billionaire and entrepreneur, was in town for a playoff game between the Mavericks and Blazers, he later told police, and dropped by the club with a group of friends. Throughout the visit, people snapped photos with the celebrity. The woman said she posed for a picture with Cuban on the advice of a friend.

She told police Cuban put his hand down the back of her jeans and groped her while the picture was being taken. The woman said she also told her friend and boyfriend the same night.

The woman said she was hesitant to come forward but also wanted the incident documented. She did not want criminal charges filed, she said, according to the report.

But the nature of the incident, a potential charge of second-degree sexual abuse, prompted a criminal investigation.

Police spoke with four Barrel Room employees who worked that night and none said they noticed anything unusual.

The same went for NBA star Kevin Love, a Lake Oswego high school graduate, who spent part of the evening at the club with Cuban. He also told police he didn't see or hear anything.

But the woman's friend told police that Cuban appeared very drunk, the report says. The friend also told police Cuban's accuser pulled her outside right after the incident and told her what happened.

The woman later submitted seven cellphone images to police as evidence. In one of his reports, Detective Brendan McGuire described two of the photos as "significant."

Those photos captured what looked like Cuban reaching down behind the woman toward her buttocks, the detective wrote. He also zeroed in on the woman's expression.

"Her teeth are clenched, eyes wider than the other pictures and brow raised showing a look of surprise and strain," wrote McGuire, a 22-year bureau veteran.

About a month after the woman first contacted police, investigators reached out to Cuban.

In a phone interview, the pro basketball team owner acknowledged he had been at the Barrel Room that evening and had been drinking.

"I wasn't sloshed but I wasn't sober, either," Cuban said, according to a transcript of the recorded conversation with the detective.

But the Dallas owner expressed dismay and disbelief when he learned of the allegations, and he strongly denied the woman's claims.

Cuban repeatedly expressed concern that he would have difficulty defending himself in court.

"Nothing happened, but when you're high profile, it doesn't, it's never just about nothing happening," he said. Cuban is also one of the stars on the ABC reality show "Shark Tank."

Portland defense attorney Stephen Houze, who would go on to represent Cuban during the police investigation, later gave authorities the results of a polygraph examination he had his client take, the report shows. He also provided two medical experts who concluded the billionaire couldn't have groped the woman.

According to the information Houze provided, Cuban was asked three questions in the polygraph exam: "While in the bar did you commit any sexual act?" "While in the bar did you stick your finger in any woman's vagina?" "In this case have you lied to your attorney in any way?"

Cuban answered no to all three questions, and the examiner concluded he was telling the truth.

The two doctors, both from the George Washington University School of Medicine & Health Sciences in Washington, D.C., reviewed the allegations. They provided written opinions claiming it would have been impossible for Cuban to penetrate the woman's vagina with his finger given the physical circumstances of the alleged incident.

One independent eyewitness this week said he saw Cuban in the Barrel Room with his entourage and saw him put his arm around a woman for a photo.

"She definitely jumped after he had put his arm around her," said Christopher White, who worked at the club between 2010 and 2014.

The woman looked upset and began to raise her voice and point angrily at Cuban, White told The Oregonian/OregonLive in a phone interview. Security guards moved quickly to separate her and other club patrons from the celebrity, he said.

White also claimed Cuban had been inebriated to the point he was refused drinks and eventually was asked to leave. He said Cuban beckoned women to pose in photographs with him throughout the night.

The way Cuban touched some of the women struck White as unseemly because his hands moved well below the middle of their backs, he said.

"He was, like, really kind of gropey toward them," White said. "It just wasn't how you'd normally pose in a picture with someone."

Police never interviewed White, who said he is relying on his memory of events from seven years ago. The police report lists several employees who were interviewed and said they saw nothing unusual that night.

Ultimately, the Multnomah County District Attorney's Office balked at pursuing criminal charges, documents show.

Deputy District Attorney Donald Rees cited a lack of concrete evidence as well as the woman's desire not to proceed with a criminal case, according to a decline to prosecute memo.

Rees also said the polygraph test and physicians' opinions offered "significant evidence" against the woman's claims.

"I have concluded no crime can be proven beyond a reasonable doubt," Rees wrote in the July 27, 2011, memo.

But the resurfaced allegations are now causing a stir.

The revelations come two weeks after Sports Illustrated detailed years of sexual harassment and misconduct allegations within the Dallas Mavericks' organization. While Cuban, who has owned the team since 2000, was not implicated in the accusations, the report raised questions about what he knew and when.

The NBA announced this week that it is reviewing the allegations against Cuban and the decision by prosecutors not to pursue the case, but offered no additional details.

"Once again, this didn't happen," said Houze, Cuban's lawyer, who also criticized the Barrel Room employee who spoke with The Oregonian/OregonLive.

"This former employee's claims about Mr. Cuban's interactions with other patrons and employees are directly refuted by all the witnesses who were interviewed by the police."

Mavericks coach Rick Carlisle blasted the allegations in an interview with The Dallas Morning News.

"Have you ever heard the term fake news? This is the most insidious form," Carlisle said Thursday.

The woman, who is now in her 30s, has not backed down from what she said happened to her seven years ago.

"I filed the report because what he did was wrong," she said in an interview with Willamette Week. "I stand behind that report 1,000 percent."

-- Shane Dixon Kavanaugh

skavanaugh@oregonian.com

503-294-7632 II @shanedkavanaugh