BOSTON -- A former YMCA girls basketball coach pleaded guilty Monday to 20 charges, including crimes of forcible child rape committed against two victims that he coached and multiple child pornography crimes for using hidden cameras to film his sexual assaults of the victims without their knowledge, Middlesex District Attorney Gerry Leone said.

James Conner, 52, of North Reading, plead guilty in Middlesex Superior Court to five counts of rape of child by force; four counts of indecent assault and battery on a child; two counts of posing a child in a state of nudity; posing a child in sexual conduct; four counts of possessing child pornography; photographing or videotaping a nude person without their knowledge; interception of oral communications; and intimidation of a witness.

Middlesex Superior Court Judge S. Jane Haggerty sentenced Conner to 20 to 30 years in state prison, followed by 10 years supervised probation.

“This defendant is a predator in every sense of the word, taking advantage of his position of authority and preying on young, vulnerable children, while documenting the extremely disturbing crimes on video tape,” Leone said.

Investigators said Conner assaulted the victims during several years at his home in North Reading and at YMCA after-school programs. Both victims were under the age of 14 at the times the assaults occurred. Conner used a hidden camera to both video and audio record himself sexually assaulting the victims, as well as filming the victims in various states of nudity and engaged in sexual conduct, without their knowledge or consent.

The video and audio recordings of the crimes being committed were recovered as a result of a search warrant executed at Conner's home at the time of his arrest. Investigators also found several thousand images and videos of children unrelated to the investigation on Conner's external computer hard drive.

Conner was arrested on Feb. 12, 2009, at his home in North Reading. He was indicted by a Middlesex County grand jury and arraigned in April, 2009.