Robert F. Bukaty / AP file

Mark Strong Sr., seen in January in Portland, Maine.

ALFRED, Maine -- Prosecutors have shown jurors videos demonstrating that an insurance agent was familiar with paid sex acts involving his mistress, but a defense lawyer said it doesn't prove that the man promoted prostitution.

The jury in the trial of Mark Strong Sr. watched a 45-minute video Thursday showing a sexual encounter between Zumba fitness instructor Alexis Wright and a man who left $250 cash on her massage table. 

Testimony indicated Strong watched the sexual encounters in Kennebunk through a live video call to his office 100 miles away in Thomaston. 

Defense lawyer Daniel Lilley contends Strong committed no crime because he neither recruited clients nor profited from the operation. 

"Observing a person in a criminal act is not a criminal act itself," Lilley told reporters Thursday outside the courthouse. 

After a week of testimony, the lead investigator, Kennebunk police officer Audra Presby, testified briefly late Thursday afternoon, and she was due to return to the witness stand on Friday. 

Strong, 57, of Thomaston, faces 13 counts that relate to promoting prostitution. A judge previously dismissed 46 counts of invasion of privacy over prostitution clients who were said to have been videotaped without their knowledge. 

Prosecutors have more than 150 videos but showed jurors only a single 45-minute recording Thursday that depicted Wright chatting with an older man who arrived and immediately began undressing. After their sexual encounter, she used disposable wipes to clean up, escorted the man to the door and then spoke to another man, believed to be Strong, at the other end of a Skype chat. 

Jurors showed little reaction as they watched the sexually explicit video on a large screen. One looked away during parts of it, one fiddled with an eyeglass case, another twiddled his thumbs and several stole glances at a clock. 

Also Thursday, computer expert Frederick Williams told jurors how he recovered a ledger from Wright's computer that described entries for sexual encounters from Oct. 5, 2010 through Feb. 13, 2012, the day before police raided her office and studio in Kennebunk and her home in Wells. 

One ledger entry showed a payment of $500 for a sexual encounter, Williams said. 

Williams, a Saco police detective, was able to match videotaped sexual encounters recovered from Wright's computers and hard drives with Skype video snapshots of the same encounters on Strong's computer in his Thomaston office. 

Other videos shown to jurors indicated Wright and Strong chatted via Skype before and after her sexual encounters, discussing scheduling and birth control, among other topics. Wright provided clients' license plate numbers to Strong, who also was a private investigator. 

Before each of the encounters, Wright took a moment to ensure the video camera was hidden. "OK, here we go. I'm locking my screen," she told Strong on one video call. 

The prostitution scandal attracted attention last fall after it was reported that Wright's ledgers indicated she made $150,000 over 18 months. 

Strong contends he had an affair with 30-year-old Wright and helped finance her Pura Vida dance studio in Kennebunk but didn't promote prostitution. Prosecutors contended the videos proved he was familiar with the details of Wright's business. She will be tried separately later.