This story is the last of three parts.

You might assume the offer comes in the form of a question. More likely, it’s accomplished with a deliberate touch, tug or tickle.

“Here?” asked the masseuse, touching the customer’s genitals beneath a hot towel.

“No thank you,” answered the customer, who tape-recorded the conversation on March 8.

In that business in Des Moines’ lower Beaver neighborhood, two signs hang near the massage table.

One says: “We do not provide any kind of sexual service!!!!”

The other: “Tips!!! Appreciated! Thank you!”

Watchdog sent two men this month into three Des Moines massage parlors, choosing locations that have been the subject of numerous reviews on a website in which paid subscribers compare erotic massage and “happy endings.”

In all three instances, the men were asked to pay $60 for a massage, plus tip. Toward the end of each massage, without forewarning, the women performing the massage touched or tickled the male customers in a sexual manner at or near their genitals.

In each tape-recorded interaction, the masseuse did not ask explicitly if the man wanted her to perform a sex act. But the men said each woman made clear one was in the offing.

PART 1:Iowa is a hot spot for trafficking in the illicit massage industry, but prosecutions are rare

PART 2: Care about human trafficking? This Urbandale man did something about it

One of the women, when questioned about her actions, said “only massage” while touching the man’s genitals.

Over the past six years, neighbors, licensed massage therapists and businesses around the city have raised concerns with Des Moines leaders about the city’s growing illicit massage industry.

In the past year, Des Moines police made major arrests of sex traffickers — including seven people indicted last summer in a ring that included 26 victims. Those arrests yielded the most convictions in sex trafficking by federal prosecutors in Iowa’s southern district.

But no major arrests for sex trafficking, racketeering, prostitution or money laundering have happened related to illicit massage parlors in Iowa's capital city.

In the past two months, stings at massage parlors in Florida and Washington have yielded dozens of arrests tied to suspected sex trafficking operations.

In the unusually large sting Feb. 19 that led to the shutdown of 10 parlors and the arrest of billionaire Robert Kraft in Florida, investigations found, as others have, that the women involved were rotated between different locations.

The Metropolitan Bureau of Investigation, one of the law enforcement agencies involved, said in the warrant application that central Florida has seen an increase in "Asian themed massage parlors," which were "typically fronts for prostitution and money laundering" that "pose a health risk to the general public for the spread of sexually transmitted diseases."

In another large bust that resulted in 26 women being freed from trafficking in Seattle, investigators found the women had come from China with the hope of making money to support their families overseas.

The women told police they replied to what they thought were legal advertisements, but found they were false when they got to the United States. The alleged victims were prostituted up to 20 hours a day, and their movements were restricted and monitored by those in charge of the criminal operations, police said.

But such investigations take considerable resources and time: The Seattle operation was three and a half years in the making, police said.

Des Moines police promise more attention

At least 13 Asian massage or reflexology parlors, most cash-only businesses, are advertising in Des Moines, Watchdog found. That’s more than when the capital city was listed as one of the top 100 human trafficking sites in the country in 2016 by the Polaris Project, which runs the National Human Trafficking Hotline.

The cities of Urbandale and Johnston have managed to shut down nearly all illicit massage parlors in their jurisdictions using local ordinances similar to others passed around the state in the past two years.

In December, Des Moines Police Chief Dana Wingert said publicly that local police would begin doing more to shut down operators who lacked valid state licenses. Wingert said enforcement would come through compliance checks or public complaints.

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This month, a police spokesman said the department cannot talk about any ongoing investigations.

“The nature of these cases, particularly the unique circumstances and dangers presented to the victims, requires confidentiality,” Sgt. Paul Parizek said.

In a statement sent to Watchdog, Chief Wingert said metro law enforcement, as well as the Polk County Attorney’s Office and the U.S. Attorney’s Office, have all agreed to commit resources to aid in the investigation and prosecution of criminal violations at “rogue establishments.”

“Nearly every city in central Iowa has since drafted and/or adopted an ordinance that allows local law enforcement to investigate these businesses, using licensing requirements based on local ordinance to ensure compliance and as a means of effectively investigating the underlying, previously mentioned criminal implications,” Wingert wrote.

Same red flags: Long hours, male clientele

Watchdog initiated the visits this month to the three parlors to see if they shared the same characteristics as others found to be involved in illicit crime.

Each of the parlors was open long hours, frequented almost exclusively by male clientele when observed by Watchdog and others, and received numerous reviews online by “erotic massage” subscribers.

All three of the women who performed massages were of Chinese descent.

One of the masseuses, who appeared to be in her early 50s, said she came from New York and had lived in Des Moines a month. Another, also appearing in her 50s, declined a reporter’s questions, appearing not to understand English. The third said she had come from China, lived in the U.S. for two years and was 38 years old.

All the women pressed the men for tips. One wanted $40 for a $60 massage, though her sexual gesture was refused. Only one took tips by credit card.

Watchdog is not naming the locales because none faces any kind of official sanction to date. But Des Moines police were informed of the locations and alleged criminal activity.

“What you describe here is a crime; assault at a minimum, and potentially assault with intent to commit sex abuse,” Parizek wrote Watchdog.

“Our investigators are trained to manage these cases, have been successful, and recognize that people who may appear to be offenders … are actually victims of sex/human trafficking. We work closely with agencies and organizations who can provide these victims with support resources, while we investigate the case.”

Workers at parlors have little choice

A bevy of research and past criminal investigations have shown that the largely immigrant women who work in illicit massage parlors — which are now estimated at roughly 9,000 across the U.S. — typically have little choice but to participate in the sex trade.

The vast majority have come from China or South Korea, speak little or no English, are mothers in their mid-30s to late 50s, and carry debts or face other extreme financial pressures, according to Polaris.

In the Midwest, most of the businesses open at 9 a.m. and don’t close until 10 p.m.

Experts say the women working have different arrangements with their employers, but many work only for tips. Some are charged fees by their employers to work at the spa. Most are driven to and from work by their employers.

“This is not by choice. They are slaves,” said Kellie Markey, who runs Dorothy’s House, a longtime residential home for sex trafficking victims. “The only choice that is involved for a woman involved in this situation is whether she lives or dies today.”

Markey’s shelter has been home to a mix of sex trafficking victims, including one woman who spoke no English who lived at Dorothy’s House for more than a year.

Markey says she’s convinced sex trafficking — which happens in massage parlors and hotels and apartments around the metro — won’t end unless law enforcement interrupts the demand.

“The only way you start to make an impact is you put buyers in jail,” Markey said. “In my mind, interrupting demand for this crime is the only way to reduce it. You have to make it so risky that people are too afraid to do it or too afraid to get caught … that they don’t do it.”

But Markey says to date, most law enforcement in Iowa act on complaints and fail to initiate investigations into the larger criminal organizations at work.

“The answer I get is, ‘We’ve got plenty of work to do.’ They aren’t out there looking for a problem.”

After police visit, parlor not closed for long

In late February, Des Moines City Councilman Chris Coleman approached Chief Wingert after a council meeting, saying the two needed to talk again about massage parlors.

Coleman said he knew Kraft’s arrest that month would prompt people to ask what the city was doing about the problem.

In 2016, Coleman and other council members began pushing the city to do more about the growth of the industry.

On Feb. 27, Watchdog contacted Coleman to ask for an update on massage parlor enforcement, driven in part by complaints about Asian Acupressure, a parlor at 852 Hull Ave. Under different names, massage businesses there have been the subject of dozens of website reviews since at least 2014.

The building that houses the business, and several others in the area, is owned by Waukee businessman George Clayton, who has not been responsive to concerns raised by city officials and the neighborhood association.

On Feb. 28, Coleman said, he was told by police that the parlor was shut down.

But that business reopened after showing police someone at the business had a state license to practice massage.

PART 1:Iowa is a hot spot for trafficking in the illicit massage industry, but prosecutions are rare

PART 2: Care about human trafficking? This Urbandale man did something about it

Lee Rood's Reader's Watchdog column helps Iowans get answers and accountability from public officials, the justice system, businesses and nonprofits. Contact her at lrood@dmreg.com, 515-284-8549 on Twitter @leerood or at Facebook.com/readerswatchdog.