After an unsuccessful three-day search, the Honolulu Fire Department has called off looking for a 74-year-old man who was last seen around Pupukea Trail, although volunteers will continue searching.

HFD began searching for Bob Walker today around 5:40 a.m. until suspending its search at about 7 p.m. The 18 HFD staff conducted a ground and aerial search today but were unable to locate Walker, who has dementia and was described as being unfamiliar with the area.

Volunteers and an Urban Search and Rescue team with a search dog and a drone assisted today.

HFD and volunteers had started looking for Walker Wednesday evening after he was last seen entering the trail head earlier that afternoon. The search for Walker continued on Thursday, Friday and today.

Though the fire department will not resume its search for Walker unless new discoveries are made. Summer Martin, Walker’s daughter-in-law, said volunteers will keep looking.

“We have a big, very coordinated volunteer search going on,” she said. “We are not stopping.”

Martin said a smaller crew has continued searching into the night every day that Walker has gone missing.

Chris Berquist, search manager for the Search Tech Advisory Team, said 120 volunteers put in 800 man hours today to look for Walker.

He said Oahu Search and Rescue, the Federal Emergency Management Agency’s Urban Search and Rescue and a Kauai search dog team make up the other volunteer groups involved.

“Our mandate is to keep going,” he said. “Once I’ve spent this much time with the family … after a couple days it becomes a very emotional experience for everybody.”

He noted that the volunteer effort picks up where the state’s stops.

Berquist, who was part of the 17-day-search for Amanda Eller last year, said the longest unresolved search he was part of was 23 days long. He said the search stopped because there was nothing else to do.

“We’re really far away from that point. We still have so much that we can do,” he said.

Berquist and Martin said they could use more help, either to help search or for other, less physically intense work.

Martin is asking prospective volunteers to wear hiking attire, bring appropriate provisions and download either the Gaia GPS or Avenza Maps application on their phones to help plot where people have looked.

A public Facebook group has been made to provide updates on the search for Walker.