Police investigating allegations of prostitution at a Zumba dance studio in Kennebunk last year thought they had uncovered a major, organized criminal network during the early stages of the case — “a substantial prostitution ring,” one officer said, and a possible “extortion” racket, said another.

A leading detective from the Maine State Police Major Crimes Unit, which usually investigates only the most serious felonies, such as homicide, even considered early on that corrupt police might be involved, helping to run license plate numbers of prostitution clients as part of a conspiracy.

A Valentine’s Day 2012 raid of Zumba instructor Alexis Wright’s dance studio, her business office and other properties left police with so much prostitution evidence — 120 hours of sex videos with cash being exchanged, meticulous ledgers and a complex coding system — it looked like they had found the first strand leading to a more complex web of crime, police said.

Those details of the police investigation came out last week as police testified in the trial of Mark Strong Sr., who is accused of conspiring with Wright to promote a prostitution business.

The officers’ testimony gave a revealing look at how authorities approached the case in the early stages, escalating from a small-town police case to a multi-agency investigation with the state’s top detectives and assistance from federal agents and inspectors.

The police witnesses also explained how some of those worst-case scenarios came to be discounted as they gathered details and analyzed evidence seized from Strong’s Thomaston properties in July 2012.

In the end, Strong, 57, of Thomaston, was the only person arrested and held in jail for any length of time. Wright, 30, of Wells, was the only one charged as a prostitute or accused of any crime more serious than a misdemeanor. Strong and Wright were both indicted in October 2012, and since then 66 people have been charged with the misdemeanor crime of engaging a prostitute, punishable by a fine of up to $1,000.

Strong’s trial in York County Superior Court is now entering its third week. About 20 witnesses have testified, with legal challenge after legal challenge slowing the trial’s progress. Prosecutors announced over the weekend that they plan to call eight more witnesses. And Strong’s defense attorneys planned to call at least 10 of their own witnesses.

Strong has pleaded not guilty to 13 charges: 12 counts of promotion of prostitution and one count of conspiracy to promote prostitution, all Class D misdemeanors punishable by possible jail time and fines.

Wright is scheduled to stand trial in May on 106 counts, including promotion of prostitution, engaging in prostitution, violation of privacy, conspiracy, tax offenses and receiving welfare benefits when ineligible. She has also pleaded not guilty.

The case began in September 2011, when Kennebunk Police Officer Audra Presby was assigned to investigate anonymous complaints left on the department’s tips line that prostitution was taking place at the Pura Vida Zumba studio at 8 York St.

Presby testified that in the months leading up to the February 2012 raids on Wright’s properties, she had uncovered very little information from surveillance and interviews to shed light on the prostitution complaints coming in to her department.

“We were still trying to confirm all these suspicious-activity calls,” Presby said.

Then, on Feb. 9, 2012, she said she was approached by Christopher West, Wright’s landlord at her 1 High St. business office. West told her he had heard “moaning and groaning” coming from Wright’s rented space. West was the first civilian witness she had spoken to in person at that point in the investigation.

Within a week, Presby went from having nothing solid to police uncovering so much computer, video and cellphone evidence that she thought she had discovered a “substantial prostitution ring,” she testified Friday.

“The complexity of the investigation was overwhelming to me,” Presby said.

Kennebunk police scheduled a meeting later that month with York County Deputy District Attorney Justina McGettigan after a detective from the Saco Police Department who specializes in computer analysis returned a report cataloging the quantity of evidence his work had uncovered.

Presby said that once she got forensic results back on Wright’s cellphone and computer equipment, including hours of video footage with Strong’s voice on every video, she made the determination that Strong was a “pimp or boss.”

“Given the totality of all the video evidence and the forensics, I couldn’t do this as a patrol officer. We have only one detective in Kennebunk, and I am not a detective,” Presby testified. “I said: ‘Based on what we have right here, this is going to be a large investigation; we’re going to need some help.’ “

By March 2012, the Maine State Police detective specializing in cellphone analysis, Leonard Bolton, had been assigned to the case, followed by a detective from the Major Crimes Unit, Sgt. Mark Holmquist, in April 2012.

With Holmquist’s help, Kennebunk police began interviewing clients from Wright’s list of more than 150 names.

“We were seeking to identify the male subjects from Ms. Wright’s videos,” Presby said. “We began to conduct interviews with what we had begun to call all the ‘johns,’ Ms. Wright’s clients.”

Holmquist testified last week that into May 2012 he was looking into extortion and whether any of Wright’s clients were connected to Strong.

“We were going to take a small percentage of the list and the most prominent ones and interview them to see if there was any extortion going on,” Holmquist said.

Holmquist explained that by “prominent,” he meant “folks who would have good lines of work, who might have good access to money.”

He said he was also looking into records that several different police agencies had run the license plate numbers of Wright’s clients through a state Bureau of Motor Vehicles database. In multiple videos, Wright can be heard asking a man off camera to run the plates of Wright’s clients as they arrived.

Holmquist said he thought at the time that he had reason to believe police were running plates for illegitimate reasons, as part of the prostitution operation.

“At the time, I wasn’t aware that a private investigator had access to BMV records,” Holmquist said.

Holmquist stayed on the case and was joined by a team of other Major Crimes Unit detectives and state police crime scene investigators on July 10, 2012, for the raids at Strong’s properties in Thomaston.

But within weeks after the raids in Thomaston, Holmquist withdrew from the case, leaving the rest of the investigation to the Kennebunk police to lead.

Scott Dolan can be contacted at 791-6304 or at:

sdolan@mainetoday.com