LEWISTON — A local man convicted in 1986 for his role in a notorious child sex ring operating in Waterville has been sent back to prison for violating conditions of probation.

Foster James McClure, 56, of 131 Bartlett St., was ordered to complete the final eight years of his sentence Tuesday for attending a high school robotics competition in Lewiston last month in the company of another registered sex offender.

That sex offender was Brian Morin, 29, a Lewiston transient, who is now being held without bail in Androscoggin County Jail on three charges of arson in connection with fires set last month that destroyed two buildings and damaged a third in the city’s downtown.

Morin was convicted in 2002 of unlawful sexual contact.

Prosecutors say McClure violated probation by having contact with children under 18 and associating with another sex offender.

McClure was convicted of two counts of rape, four counts of gross sexual misconduct, four counts of unlawful sexual conduct and one count of sexual abuse of a minor in 1986. He was one of six people charged in 1985 with sexually assaulting more than six children — ages 4 to 14 — over six years in Kennebec County.

At the time of that arrest, McClure was serving a prison term for gross sexual misconduct and unlawful sexual contact with a boy and girl under the age of 5, according to a 1986 Associated Press report.

According to prosecutors, McClure attended the robotics competition in Lewiston in April. People contacted police because McClure and Morin were videotaping competitors, and some of the students reported they were uncomfortable with the men’s activities.

McClure’s attorney told the Morning Sentinel that Morin, not McClure, was doing the videotaping.

McClure pleaded guilty in 1986 to the sex assault charges and was sentenced to 20 years in prison, with all but 15 years suspended, and 12 years of probation. He was released early under the state’s former good-time rules in 2008.

According to the Waterville Sentinel, McClure and others involved in the sex ring abused and assaulted the children and prostituted one 10-year-old girl for as little as $1 per session.

Previous convictions include two counts of gross sexual misconduct and two counts of unlawful sexual contact, also in Kennebec County.

According to Maine’s Sex Offender Registry, McClure is a lifetime registrant.