As Donald Trump's New York legal troubles began to mount this spring, his lawyers and political action committee sought the help of Sean Crowley, a local private eye.

Save America, a PAC founded by the former president, paid $152,285.50 to Crowley's firm in April and May, according to federal campaign filings. He was paid for work related to Trump's Manhattan court cases.

It is unclear what that work entailed.

Crowley, a former New York police captain, declined to discuss his work when contacted by CBS News.

"I think you should be talking to the attorneys regarding anything related to me and the PAC," Crowley said.

Asked which case Crowley's work was related to, attorney Joe Tacopina replied, "I think both."

Tacopina, who represented Trump at his April 4 criminal arraignment in Manhattan and argued on his behalf in a May civil rape and defamation trial, would not provide more details about the private investigator's work for the Trump team.

"Can't go into that," Tacopina said.

In the criminal case, Trump entered a not guilty plea to 34 state felony counts of falsification of business records. In the civil case, a federal jury found Trump liable for sexual abuse and defamation of the writer E. Jean Carroll. It did not find him liable for rape, though the judge later concluded Carroll's assertion that Trump raped her was "substantially true."

When asked what Crowley's work entailed, another Trump attorney, Susan Necheles replied, "I have no comment about what Crowley is doing."

"Obviously what the attorneys and investigators are doing to prepare for trial is privileged," Necheles said.

Save America's Federal Election Commission filings describe the payments as being for "research consulting." Crowley's firm, CTS Research & Investigation, is listed as just "CTS Research" in the filings.

Save America did not reply to questions sent by CBS News. Spokespeople for Manhattan District Attorney Alvin Bragg, and Roberta Kaplan, an attorney for Carroll, declined to comment.

The key witness in Trump's Manhattan criminal case, his former attorney and "fixer" Michael Cohen, has suspicions.

"I have seen people take photos of me in a way that can only be described as unusual," Cohen said. "Just about a month ago, I noticed a man photographing me outside my home – what he believed was clandestine. I wouldn't be shocked if they were hired by Donald to gather intel on me to use at the upcoming trial cross-examinations."

But Necheles said Cohen's theory was off-base.

"I will say, we have no need to send an investigator to take a photo of Michael Cohen. He loves to be on TV, so we would have plenty of pictures or video of him if we needed them," Necheles said.

Crowley's firm, CTS Research & Investigation, is headquartered in a small Brooklyn storefront shop, where he also works as an accountant. The awning over the door says "Crowley & Sons Income Tax." 

Soon after founding CTS, he also had a brush with television. 

In 2009, he appeared in a show called "Medium P.I.," described by the Internet Movie Database as a television special about a private investigator and a psychic teaming up "to solve the tragic case of a young man. Murder or Suicide?"

Not long after that, he was hired to protect the baseball star Aroldis Chapman and arrange logistics for the Cuban-born athlete who was defecting to the United States, according to the Chicago Tribune.

Closer to home, in 2015, the family of a teenage girl who'd been lured to California by a man she met on social media credited Crowley with tracking her down, according to the Staten Island Advance. Crowley told the paper he solved her alleged kidnapping using phone and flight records, and "a little bit of gut feelings."  

Another private investigator, who asked not to be identified, described Crowley as "ethical."

"I've known Sean for a long time. Sean is a principled guy. There are investigators that would do unethical, unprincipled things. Sean is not that kind of person," the private investigator said. "Any law firm defending someone accused of what Trump was accused of would absolutely hire an investigative firm as part of it. If you didn't hire an investigator to prepare for the defense you'd be incompetent."

But the question of whether this is the kind of legal expense a political campaign should be covering is a "gray area," according to Columbia Law School professor Richard Briffault.

"The real question is how far does the idea of legal expense go? And that's something I think that election law really hasn't thought very much about," Briffault said.

Save America has spent more than $40 million on legal costs for Trump and his allies. Earlier this year, the Trump campaign made a tenfold increase in the percentage of supporters' donations it committed to Save America, from 1% to 10%. The PAC had run through most of its funds by the end of the second quarter of this year and had just $3.7 million in total cash on hand by the end of June, according to its FEC filing.

Trump's campaign spokesperson Steven Cheung said earlier this month that the funding was required "to combat" investigations and criminal charges against Trump, and his aides and allies.

"To protect these innocent people from financial ruin and prevent their lives from being completely destroyed," Cheung said.

In:
• Donald Trump

Graham Kates is an investigative reporter covering criminal justice, privacy issues and information security for CBS News Digital. Contact Graham at [email protected] or [email protected]