03/20/2013 03:20 pm ET Updated May 20, 2013

Dylan Redwine Missing: Leads, Reported Sightings Turn Up No New Evidence, La Plata Sheriff Says

Two of the most publicized leads in the Dylan Redwine case have failed to turn up any new evidence, the La Plata County Sheriff's office said on Tuesday.

On the day Dylan went missing, Nov. 19, 2012, a man reported seeing two boys walking alongside La Plata County 501, but investigators say they located the boys and determined they had nothing to do with the teen's disappearance.

A stranger who was seen in the community asking where to buy gas that same day was also ruled out in February.

Dylan, 14, had been spending a court-ordered Thanksgiving visit with his father Mark Redwine when his father reported him missing from the home. Mark Redwine contacted the Bayfield Marshal's Office that day to ask for help finding Dylan, and the teen's mother contacted the La Plata County Sheriff's Office to report the disappearance.

Authorities have said that they do not believe Dylan ran away, in part because he has his cellphone and has not contacted any of his friends.

A week after the disappearance, investigators served a search warrant on Mark Redwine's home, while search teams have been using cadaver dogs and divers to search the Vallecito Lake-area.

"Mark's and Dylan's interactions and activities within the community on November 18th and 19th, as well as tips related to persons, locations and sightings remain under investigation," the sheriff's office told The Denver Post.

In February, Dylan's parents taped a heated segment on Dr. Phil.

"I didn't lose Dylan," Mark Redwine said on the taped segment.

"Then why is he gone?" Dylan's mother Elaine Redwine asks. "You have to answer that question. You had him, where is he?"

Anyone with information about the disappearance of Dylan Redwine is being asked to call a tip line at 970-382-7511, or the Durango-La Plata Crime Stoppers at 970-247-1112. There is a reward of more than $50,000.