NEWMARKET, N.H. (AP) – A convicted sex offender who chaperoned an elementary school field trip was missing from the state’s list of registered sex offenders, according to the Newmarket Schools superintendent.

Dennis Pratte, 50, of Newmarket, turned himself in to police last month. He pleaded guilty in 1994 to two charges of aggravated sexual assault on a juvenile and was required to stay away from children.

Pratte was a Newmarket police officer from 1974 until he resigned in 1994, after the charges against him came to light. He is currently out on bail and is scheduled to be arraigned in Exeter District Court on Oct. 13. He also faces a new aggravated felonious sexual assault charge in connection with an incident in 2003 involving an adult.

Pratte is subject to annual registration with police and having information about him posted on New Hampshire’s online Sex Offender Registry. But he was missing from the list when he was one of 20 parent chaperones on a Newmarket Elementary School field trip, said Kathleen Murphy, school superintendent.

Murphy, who discussed the matter with the Newmarket School Board on Thursday, acknowledged, however, that it was after-the-fact information and school officials never ran his name through either a criminal-background check or the registry. Police Chief Kevin Cyr said Pratte registered with his department as required and police forwarded that information to State Police in Concord. But somehow the information never made it onto the Sex Offender Registry.

According to a representative from the state’s Sex Offender Registry, Pratte wasn’t listed on the registry from its inception in 1999 until this past April because his criminal record indicated his victim was over age 13.

In April, the registry was informed there were two offense dates on Pratte’s record, one when the victim was under 13 and one when the victim was over age 13.

“Unless we get a copy of every single indictment and every single registration, it’s very hard to obtain the information,” said Denise Perry, the state’s Sex Offender Registry coordinator. She could not say how her department received the updated information in April.

In March, Pratte accompanied students on a trip to Exchange City in Portsmouth. At the time, Murphy said there were no warning signs that Pratte lived in the same house as one of the students, drove the student to and from school and was the name listed as the primary emergency contact.

School officials said they were notified by state police of Pratte’s criminal record in mid-August, but did not inform parents until Sept. 26 when they sent home a sealed letter detailing the situation.

“We did not want in any way to jeopardize his case,” Murphy said.