ALFRED — A key defense claim that an insurance agent charged with helping a Zumba instructor run a prostitution business was unfairly targeted because he was investigating Kennebunk police was raised by the man’s brother on the same day a search warrant was served, an official testified Friday.

The brother of defendant Mark Strong Sr., who is a private investigator in addition to an insurance agent, warned state police investigators not to let any electronic evidence fall into the hands of Kennebunk police, yet a hard drive ended up with the lead investigator, a Kennebunk officer, for about 36 hours, Sgt. Mark Holmquist acknowledged.

Holmquist said he didn’t see a problem that former Officer Audra Presby ended up with the hard drive because it remained in the hands of law enforcement, ensuring the chain of custody.

But the defense contends the hard drive contained details about alleged unprofessional conduct by Presby, who was reprimanded for having an affair with her boss and was accused of abusing a 5-year-old boy. The police chief says the abuse claim was determined to be unfounded.

“My client was investigating the Kennebunk police, which had a lot of skeletons in their closet, and he got singled out in this particular case for a criminal charge in order to have him back off. We can’t find any other motive,” Strong’s lawyer, Daniel Lilley, told reporters after court.

Strong, 57, of Thomaston, is accused of helping Alexis Wright run a prostitution business out of her Zumba dance studio in the coastal town of Kennebunk. He faces 13 misdemeanor counts related to promotion of prostitution. Wright will be tried later.

Strong was having an affair with Wright and signed on as guarantor for her Zumba studio, but he didn’t know about the accusations of prostitution centered on the business, the defense contends.

Strong contends he began taking a look at the conduct of Kennebunk police after Wright told him that she was being harassed.

And his brother, attorney James Strong, backed up the notion, telling evidence technicians in July that Mark Strong had obtained “revealing evidence” about Kennebunk police, Holmquist said.

All hard drives and computers seized went to a state police computer crimes lab except one that ended up with Presby, who later delivered it to state police, he testified. “We simply overlooked that one piece of evidence,” he said.

Also Friday, an attorney for the town of Kennebunk turned over some personnel records to defense lawyers who intend to attack Presby’s credibility.

Lilley clashed with prosecutors and the town’s attorney after being told that municipal workers’ personnel records were confidential under state law and that disciplinary actions against officers were purged because of union rules.

Minutes later, Kennebunk police Chief Robert MacKenzie testified under cross-examination that the records still exist, even after being removed from an officer’s personnel file. He also confirmed that a Presby reprimand was once considered a public record.

The matter of records will be revisited next week before Presby testifies. Lilley contends his client’s rights in a criminal matter trump state civil law that makes personnel records confidential.

Still pending was a motion by Lilley to dismiss the remaining 13 counts because of discovery violations by prosecutors. “This is about the third or fourth time that we’ve complained about the state not furnishing documents. So at this point, we think the sanction should be extreme,” Lilley said.