Feb. 5, 2018 update: Arnott was convicted of interference and two breaches of undertaking. The child pornography charges were withdrawn by the prosecution.

A young man who was the last person to see a missing B.C. teenager alive has been charged with sex offences against another girl.

Bowen Island resident Gavin Arnott, 22, is charged with sexual interference and possession of child pornography for allegedly keeping illicit photographs of a 14-year-old on a cell phone and computer. He was arrested two weeks ago after allegedly threatening her.

Arnott is a person of interest in the suspicious disappearance of his ex-girlfriend, Jodi Henrickson, who was last seen at a house party on Bowen Island on June 20, 2009. Police are treating Henrickson's case as a homicide, and believe that her body is buried somewhere on the island.

The 17-year-old Squamish girl had spoken to her parents the day before she disappeared, telling them that she was going camping for the weekend.

Arnott told CTV News in 2009 that he last saw Henrickson on the side of a road after the party. He said that they had an argument and she walked off, never to be seen again.

At the time of Henrickson's disappearance, police said they were aware of her troubled relationship with Arnott. Just a few months before she disappeared, Henrickson called police to make an assault complaint against him, and he later pleaded guilty to the charge in court.

Arnott has been interrogated by police, who have also searched his father's Bowen Island property, but he has denied any involvement in Henrickson's disappearance.

Simon Fraser University criminologist Neil Boyd has studied the case and says it's unlikely that charges will be laid in Henrickson's suspected murder until her body is found.

"Any case in which it's alleged that there is a homicide and you don't have a body, that's difficult. It's difficult to get an arrest; it's difficult to get a conviction," he told CTV News.

"One can only infer in the case of Jody Henrickson that police and prosecutors do not believe that at this time they have a sufficient evidence to go forward."

Arnott is scheduled to appear in court Wednesday on the sexual interference and child pornography charges. He has been ordered to stay away from minors and is forbidden from possessing digital photography equipment.

With a report from CTV British Columbia's Lisa Rossington