JACKSONVILLE, Fla. -- More than four months after two boys left Paxon Middle School and never made it home, their families were joined by law enforcement and victim advocates in asking the public to continue to look for them.

The reward for information leading to the safe return of Mark Degner, 12, and Bryan Hayes, 13, was boosted to $10,000 and authorities released a newer photo of Bryan.

Authorities said Brian and Mark walked away from their school on Feb. 10. It is believed they are runaways, but investigators said they may be in danger.

"Due to the length of time since their disappearance and their inability to care for themselves, we feel they're held hostage and in danger," Darlene Briggs, Degner's grandmother, said Tuesday.

An aggressive search by the parents and Jacksonville police turned up several sightings of the boys in north Jacksonville in the first two weeks after they disappeared.

A month later, there were reports that the boys were seen in Volusia County. Another unconfirmed sighting of one of the boys near Daytona was received in the last few weeks.

"There are times of discouragement, and there are times that you're very, very hopeful," Briggs said.

"I never knew how if felt to deal with a missing child until now," Degner's mother, Linda Alligood, said.

Anyone with any information about the boys is asked to call the Jacksonville Sheriff's Office missing persons office at (904) 630-2627 or Crimestoppers of Northeast Florida at (888) 277-TIPS. Callers can remain anonymous and still be eligible for a cash reward.