PORTLAND – A former University of Maine at Farmington student will remain on the state’s sex offender registry for a child pornography conviction that was upheld Thursday by Maine’s highest court.

The Maine Supreme Judicial Court denied an appeal by Keith Nadeau, 21, of Biddeford, who pleaded guilty last year to two counts of possessing sexually explicit material depicting minors younger than 16.

Nadeau entered the guilty plea in October on the condition that he could appeal the decision. Franklin County Superior Court Justice Michaela Murphy sentenced him to nine months in jail for each charge, which he had already served when she handed down the ruling.

Nadeau was also put on probation for a year and ordered to register with the state as a sex offender — punishments that would have been overturned if the appeal was successful.

Nadeau’s appeal was based on the argument that university police violated his constitutional rights when obtaining evidence from his dorm room that was used to convict him.

In December 2007, university police seized and searched Nadeau’s computer and flash drive after another student reported that Nadeau possessed child pornography, according to court documents.

Based on a recording of a conversation between Nadeau and police, the law court concluded Nadeau had consented to the seizure of his flash drive, but that police did not have his consent to take the computer, thus violating his rights. The court ruled, however, that police eventually would have obtained the computer lawfully and, on that basis, denied the appeal.

Nadeau’s attorney, Michael Cunniff, said that although he was disappointed by the decision, it would help set a protocol for the search and seizure of computers, which has limited legal precedents. “I think there’s value in the court’s review of these circumstances,” he said.

Nadeau was indicted in April 2008 on a felony charge, as well as the two misdemeanor charges, for possession of sexually explicit materials, but the state dropped the felony charge in the plea bargain.