VANCOUVER -- Police are issuing an appeal for information in a year-long missing persons case in Vancouver.

David Sullivan, who has dementia and diabetes, was seen walking on Alexander Street near Gore Street on June 27, 2019.

He hasn't been seen since.

Sullivan was reported missing three days later, and those involved in the report said he may be disoriented and confused.

He might ask for help if located, police said last year.

Sullivan was 61 at the time.

On Monday, police said they still don't know what happened to Sullivan.

He'd been staying in an assisted living facility in Vancouver at the time of his disappearance. Police described his absence as "highly unusual."

"Despite extensive efforts, police have found no sign of him," Sgt. Aaron Roed said in an emailed statement.

Saying friends and family are desperate for answers, Roed asked anyone with information on his disappearance to come forward.

Sullivan is described as white and between 5'10" and 6'. He has a heavy build and is bald.

He was last seen wearing a red-and-white checked shirt, brown pants, and possibly sandals, and was carrying a blue duffle bag at the time.

Vancouver's missing persons unit can be reached at 604-717-2533.