MELBOURNE, Fla. -

Local 6 partner Florida Today reports that Robert "Bob" Harrison remains unaccounted for 11 days after he was reported missing.

Harrison, 80, suffers from Alzheimer's disease. The West Melbourne resident was last seen May 25 in the 3100 block of Milwaukee Avenue, just southwest of the Minton Road-Henry Avenue intersection.

"It's hard. It's hard. My grandmother is used to having him home every night," said Harrison's granddaughter, Heather Bishop of Vero Beach.

"My uncle was really close to my grandfather. And it's taken a toll, not having any answers, not knowing where to look next," Bishop said.

"We're not stopping by any means. We just wish we knew where to look," she said.

Harrison stands 5-foot-11, weighs 145 pounds, and has short gray hair and hazel eyes. He was last seen wearing jeans and a green-and-white Western-style shirt.

A "Find Bob Harrison" page has made its debut on Facebook. And a group of about 15 Texas EquuSearch volunteers searched for Harrison in vain Saturday and Sunday.

These volunteers scoured wooded areas, abandoned homes, overgrown properties and waterways — even wading through canals, said Merritt Island resident Daphne Drew, a Texas EquuSearch search coordinator.

Drew said her group awaits more information to resume its search.

"The moment that we have anything that is valid, we will be there. We will be back," she said. "We're anxious to hear something to get us back out there. We want to help the family desperately."

Brevard County Sheriff's Office personnel used bloodhounds and a helicopter to search for several days last week. The agency has scaled back its campaign, Deputy Maria Fernez said.

"We have been following up on several leads that we have received. However, those leads have not led to finding Mr. Harrison's location," Fernez said.

Bishop said Harrison previously lived in West Virginia and Texas, and he also lived in Wabasso and Gifford, a community near Vero Beach.

"It's possible that he just got up that night and decided he wanted to go to West Virginia. We don't know. We don't know if he flagged down a car and got off at an exit somewhere," Bishop said.

"But we don't want people to stop looking."