A registered sex offender has entered a conditional guilty plea to gross sexual imposition.

Matthew Crabtree, 24, entered the plea to South Central District Judge Sonna Anderson on Tuesday at the Burleigh County Courthouse. The plea is conditional because Crabtree can appeal a previously denied suppression motion to the North Dakota Supreme Court.

Crabtree was charged in September with the Class AAfelony after his probation officer learned he had a sexual encounter with a 14-year-old girl in March 2006.

According to the North Dakota attorney general's sex offender Web site, Crabtree was required to register as a sex offender for a corruption or solicitation of a minor conviction. He is registered as a low-risk offender.

According to court documents, Crabtree wanted permission to live with his wife after she gave birth to his child. His probation conditions prohibited him from having contact with juveniles.

As part of the process to get permission to live with his child, Crabtree had to fill out a questionnaire about his sexual habits and undergo a polygraph test, documents said. He wrote that since his last conviction, he had sexual contact with a girlfriend, his current wife, and had "protected sex with an acquaintance."

According to court documents, authorities learned who the acquaintance was and determined she was a 14-year-old girl in March 2006. Crabtree claimed he thought the girl was 19, but the girl and another witness said Crabtree knew she was a juvenile.

A disclaimer on the questionnaire said people filling it out are not required to give identifying information about victims, but any information given will be reported to child protective services as required by state law.

Crabtree had filed a motion to suppress the information from the questionnaire, polygraph and subsequent questioning, according to court documents. Documents said he felt his Fifth Amendment right against self incrimination was violated because he had to give the information in order to gain permission to live with his family. Without the information, authorities would not have found out about the girl, Crabtree and his attorney, Tom Tuntland, claim.

Anderson denied the motion on April 13, saying Crabtree did not have to answer the questions into his sexual history and could have chosen to accept the consequences of not living with his expected child.

If the Supreme Court decides on appeal to suppress the information from the questionnaire, polygraph and other questioning, Crabtree could withdraw his guilty plea, and case would go to trial. "We can't appeal until judgment is entered upon sentencing," Tuntland said.

Crabtree is slated to be sentenced at 11:30 a.m. July 17 following a presentence investigation. He is in the custody of the Department of Corrections and Rehabilitation for probation violations.

(Reach reporter Jenny Michael at 250-8225 or jenny.michael@;bismarcktribune.com)