DOVER, N.H. – David Cobb, the former private-school teacher imprisoned after he was caught with a backpack full of pornography while walking with a young boy in Farmington a decade ago, would rather stay in prison an extra year than admit he’s a sex offender.

Cobb, a 69-year-old former English teacher at Phillips Andover Academy who was nicknamed “Pumpkin Man” for a pumpkin mask also found in his backpack and a list of prices for various acts to be performed on “pumpkin,” is scheduled to be released in June 2007.

However, in a motion filed in Strafford County Superior Court, he asked a judge to extend his prison sentence another year rather than risk getting sent to jail a year after he leaves prison.

A one-year jail sentence for misdemeanor pornography convictions was deferred for a year after the completion of his eight- to 15-year prison term. However, because he has failed to complete sex offender programming, Cobb expects the judge to impose the deferred sentence.

“It would be difficult, impractical and cruel to family members to spend a year at home rebuilding bonds and pursing second-career opportunities only to give it all up after a year to add to a dozen years of incarceration,” he wrote in a motion filed in Strafford County Superior Court. “Better to wait and serve it all continuously.”

Cobb took part in sex offender treatment earlier this year, but was dismissed after he would not admit his guilt, according to court documents. He continues to maintain his innocence and has been fighting with prison officials for years over his classification as a sex offender.

He said he never assaulted any children; he was convicted on child pornography charges.

“I taught adolescents for four decades and supervised them in a residential school as a counselor and a dean of students with nary a complaint,” Cobb wrote a prison official. “And you apparently don’t know that I have never been charged with nor convicted of sexual assault.”

In Maine, Cobb was charged with aggravated felonious sexual assault on a 9-year-old girl and a 12-year-old boy, but pleaded guilty to a lesser charge of having unlawful sexual contact with them.

In New Hampshire, Cobb was convicted of 53 charges of displaying child pornography, 267 charges of possessing child pornography and a single count of attempted aggravated felonious sexual assault on the 12-year-old boy.

Strafford County Attorney Janice Rundles said she was not sure whether the judge has the authority to substitute an extra year in prison for the jail sentence. She has not yet formally responded to Cobb’s motion.

In his motion, Cobb also said he experienced severe breathing problems at the Strafford County jail when he was held there before trial and did not want to return.

“Despite Strafford’s nice staff, the building and cleaning chemicals are a respiratory nightmare,” Cobb wrote, “and would be worse now for lungs a decade older and more traumatized” by chemicals he uses to clean toilets and showers every day at the state prison.