PLAISTOW — A local man has been arrested after he allegedly held a cellphone over a shower curtain to snap pictures of an underage teenage girl.

John M. DeRose Jr., 40, is charged with manufacturing and possession of child sex abuse images.

DeRose was arrested Wednesday after an investigation that began on July 9 when the teenager, who is under 18, told police she saw DeRose’s cellphone over the shower curtain while she was showering.

During a follow-up interview with the Child Advocacy Center in Derry, the teen reported the incidents had occurred in February and March, Detective Ryan Garney wrote in a police affidavit.

The alleged victim said that on one occasion she believed he held the phone over the curtain for about 30 seconds and that it was placed in the right-hand corner of the shower.

Police later seized DeRose’s cellphone, which “revealed an overwhelming number of images” of the teen, police said.

“Approximately 27 thumbnail images appeared to have been taken from the exterior of the first-floor bathroom, looking into the bathroom,” Garney wrote in the affidavit.

DeRose was being held on $25,000 cash bail at Rockingham County jail in Brentwood, but it was reduced to personal recognizance.

DeRose waived arraignment on the felony charges Thursday afternoon in Rockingham County Superior Court.