GRAFTON (AP) - Jurors deliberated less than two hours before convicting a man of sexually abusing three children.

Robert Buresh, 34, was found guilty Friday on three counts of gross sexual imposition.

Judge Richard Geiger ordered a presentence investigation to include evaluation as a sex offender. A sentencing date was not immediately set.

Buresh has been in jail in Grafton since charges were filed in October 2005. He did not testify during his four-day trial.

Authorities said the abuse happened from January 2002 until June 2005, in the home where Buresh lived with the children and their mother.

The children - two girls and a boy - testified against Buresh. The courtroom was sealed during their testimony.

"The jury had the firsthand opportunity to have the children tell them, themselves," Walsh County State's Attorney Barbara Whelan said.

Buresh was not the children's biological father, Whelan said. He and their mother went through a Wiccan ceremony that does not constitute a legal marriage, she said.

Defense attorney David Dusek called April Bradley of the Family Institute in Grand Forks as a witness. Bradley testified that her study of investigators' interviews with the three children led her to question the reliability of the interviews.

The jury began deliberating at 1:45 p.m. Friday and returned with a verdict at 3:30 p.m.

Each gross sexual imposition charge is a Class A felony punishable by up to 20 years in prison.