A New Jersey state trooper has been accused of responding to an offer to sexually assault a 5-year-old girl – from the child’s own mother, according to a report.

Jeffrey Reitz, 47, of Williamstown, exchanged emails with the woman on Dec. 31, 2014, during which she suggested that he sexually assault the girl, NJ.com reported.

The trooper asked for a photo of the girl, saying he wanted to see if he would become sexually aroused, according to his criminal complaint.

After receiving the image, officials said, the sicko responded with one word: “Nice.”

He also sent the mother images of his genitals before and after she sent the photo of her daughter, authorities said.

Reitz’s revolting email exchange was discovered as a result of evidence seized in a separate probe by the Camden County Prosecutor’s Office, the news outlet reported.

The Gloucester City, NJ, woman was sentenced to seven years in prison after pleading guilty to permitting a child to engage in pornography.

A search of her cellphone revealed the emails to Reitz, according to the complaint.

Reitz was arrested Thursday on a charge of third-degree possessing child pornography and was being held at the Salem County Correctional Facility. He faces a possible sentence of three to five years in state prison and a fine of up to $15,000.

He has been suspended from the police force, where he is assigned to the Commercial Carrier Safety Inspection Unit.

Reitz’s attorney, Stuart Alterman, said his client is a 15-year police veteran and has served “without incident.”

“I met with my client today. He is going to be entering a plea of not guilty and he should be released very shortly,” Alterman said Thursday. “We will take whatever necessary steps in order to have him exonerated and restored to his position.”