BOYNTON BEACH -- A Boynton Beach city commissioner sent naked pictures of herself to her lover, eventually prompting a criminal investigation into whether a lobbyist used the photos to blackmail her, according to documents obtained by The Palm Beach Post.

Marlene Ross, a commissioner for five years, told prosecutors last month that she felt lobbyist and former Commissioner David Katz had pressured her for years, trying to sway her votes on many key issues. She even admitted she lied last year when she signed a letter saying he’d never lobbied her.

But recently, Ross told investigators, she became convinced Katz knew of the photos and grew fearful he’d use them to destroy her political career, after he mentioned them at a Sept. 4 city commission meeting.

In comments that were cryptic to most in the chambers but which Ross believed were aimed at her, Katz suggested “consequences” for voting against his close friend, former Mayor Jerry Taylor, to fill out the term of a commissioner who had resigned in July. Ross continued that night to oppose Taylor and the commission remained deadlocked, 2-2.

After interviewing Ross at least three times, prosecutors concluded that “none of the scenarios described by Ms. Ross involved behavior that could be considered criminal extortion,” Daniel Funk, assistant Palm Beach County state attorney, wrote in a memo dated Thursday.

However, a summary says, prosecutors worried about the potential for “Katz or others” to use the photos “to extort Ross in a future commission vote.”

Ross eventually quit cooperating, and the case was closed Thursday.

“This is laughable at best,” Katz said Friday. “There’s nothing to blackmail her over. That’s ridiculous.” He said Monday that he would not comment further because he hadn’t seen the prosecutors’ documents.

Ross, elected to the commission in 2007 and reelected in 2011, describes Katz — who regularly lambastes commissioners at meetings — as a man who intimidated her, even physically; once, she says, when she mentioned troubles with her boyfriend, Katz offered to have someone “take care of it.”

Of Katz, Ross wrote in a statement to prosecutors, “I can easily see that my hopes for my future career plans as a public servant are possibly being destroyed in a despicable way by a person who is corrupt and evil.”

The investigation is the latest and quite possibly the most outrageous of a series of sideshows in Palm Beach County’s third-most populous city. Amid spats erupting from the dais, Boynton Beach has struggled with plummeting property values, prolific turnover and continuous deadlock.

Mayor Jose Rodriguez was arrested this year on charges of pressuring the police chief and interim city manager to stop a child abuse investigation. He also is accused in a lawsuit against the Community Redevelopment Agency of helping get rid of its chief in part because she rejected his sexual advances.

Katz has accused the mayor of a vendetta and regularly calls out Rodriguez in public meetings.

And tow firm operator David Floering, who stopped bidding for city contracts in 2010, claiming corruptuon, has accused Rodriguez of cheating on property taxes and called the mayor a crook and a liar so many times that Rodriguez sued him for defamation; he later dropped the case.

It was Floering who told the state attorney’s office in mid-August about the photos, saying he believed that “Ross may be getting extorted to vote in a certain way.” He showed investigators an email he said was from Lisa Bright, the former CRA director. Bright said she was trying to get what she called “provocative pictures.” Bright later told prosecutors she hoped the photos would help her in her wrongful termination lawsuit.