LOVELAND, Colo. -- Dive teams came up empty-handed in their search Sunday for a 2-year-old Longmont boy who fell off a boat at Carter Lake in Larimer County.

The missing toddler had not been found as of Sunday evening, the Larimer County Sheriff's office said. The search for the boy become a recovery effort. Recovery operations have been suspended until Tuesday when technical sonar equiment is expected to arrive from out of state to aid in the search, the Sheriff's office said Sunday.

"They were making what they called their last run on the lake for the night before going home. At some point the 2-year-old fell out of the boat. No one actually saw what happened, why he fell out," said Don Nadow of the Larimer County Sheriffs office.

Sheriff's office spokeswoman Kathy Messick said a call came in at 8:08 p.m. Saturday reporting the child's disappearance. Dive teams from three agencies and authorities on foot searched until almost midnight, resuming the search Sunday morning.

Searchers sectioned off part of the lake Sunday. Dive rescue teams used underwater cameras and sophisticated sonar equipment in the search. They searched to 130-foot depth. Beyond that rescuers had no visibility.

The incident occurred about 250 to 300 yards offshore from Dam 1. The depth of the lake in this area was estimated to be about 105 feet, Messick said. The boy was with his father and one other adult, and a 3-year-old child.

"They found a life vest. They don't know if he came out of his life vest or if it came out of the boat," Messick said. The life vest was found unbuckled in at least one place.

Anyone with information about the missing boy was asked to call the Larimer County Sheriff's Office at 970-498-5200.

The family asked that the boy's name not be released until they were able to notify out-of-town family.