FOREST LAKES, Ariz. -- The body of a Chandler planning commissioner missing since Jan. 2 has been found by four Phoenix-area residents walking along the shore of Chevlon Canyon Lake, 12 miles northwest of his second home in Forest Lakes in northern Arizona.

An autopsy performed Monday confirmed the remains are those of Mark Russell Irby, 51, deputies said. Identification was made by a Flagstaff dentist using dental records.

The medical examiner has yet to determine the cause and manner of death.

Irby was the subject of an extensive search after he was reported missing while on an all-terrain vehicle ride in the area of the Forest Lakes subdivision.

His ATV was found abandoned in the forest on March 14, about 10 miles away from the subdivision.

Irby's body was found about 12 miles northwest of the subdivision and approximately 2.2 miles from the ATV, the Coconino County Sheriff's Office said.

Friends and family had offered a $5,000 reward for information leading to his whereabouts.