By Dan Goldberg

and Tomas Dinges / The Star-Ledger

SOUTH PLAINFIELD — A retired South Plainfield police captain who helped create a computer forensic laboratory that investigated crimes against children was charged today with sexually exploiting an underage girl and encouraging her to perform sexually explicit acts on the internet, U.S. Attorney Paul Fishman said.

The girl, who was not named, told federal agents that Michael Grennier, 50, paid her for photographs and video of herself naked and partially clothed, according to the criminal complaint. On some occasions, Grennier photographed and videotaped her, the complaint says.

The girl, according to the complaint, also told the FBI that Grennier paid her to engage in sexually explicit acts with another underage girl at a New Jersey hotel while he watched via webcam. Grennier paid the two girls a total of $500, the complaint said.

Grennier was allegedly going to purchase about $175 worth of merchandise for the girl in exchange for some of these acts, the last of which happened on Thursday, according to text messages between the two that are documented in the complaint.

According to the complaint, the FBI searched the girl’s New Jersey home on Friday. Grennier was arrested the same day, South Plainfield Mayor Matthew Anesh said last night.

Late last year, the South Plainfield Police Department began looking into a complaint regarding Grennier and forwarded it to the FBI, Anesh said.

Grennier retired from the force in 2006 after rising to the rank of captain, the mayor said. Records show he was employed there for 25 years.

His tenure with the department was characterized by achievements involving computers.

In 1986, he was described as the department’s "computer guru," according to the borough’s website. That same year, he garnered international media attention after cracking a case of widespread computer fraud by local juveniles. According to the website, the case was considered one of the "earliest investigations involving computers as a tool to commit a crime."

One year later, Grennier was named the department’s Officer of the Year.

In 2001, he helped set up a computer forensic laboratory at the police department, according to news reports and the mayor. At the time, officials said Grennier and another officer were trained to investigate various computer crimes, including fraud and those involving people who preyed on minors.

Upon retirement, Grennier remained employed as a consultant for several years managing the borough’s information technology, Mayor Matthew Anesh said.

"Few crimes are more troubling than those involving children, especially involving the exploitation of children," the mayor said.

According to the federal complaint, Grennier’s relationship with one of the girls goes back "several years," but it does not provide any further details.

The charge of sexual exploitation of children carries a mandatory minimum penalty of 15 years in prison, a maximum potential penalty of 30 years in prison and a $250,000 fine.

"It’s a despicable crime," Anesh said. "and it’s a tough thing, as a close-knit community, to deal with."

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