NEW YORK (CBSNewYork) – Family and friends mounted a massive search Thursday for a grandmother who’s been missing for more than three days.

They’re hoping to find a clue as to where 88-year-old Mary Joyce-Bonsignore might have wandered off to.

Mary Joyce-Bonsignore (credit: Connor Coyne/NYPD)

The Bath Beach, Brooklyn resident has dementia. She was last seen by her husband Monday morning.

“He went out to take the garbage out, and she took off in two seconds and ran off,” her grandson, Conor Coyne, told CBS2’s Valeria Castro.

It’s believed she walked down 19th Avenue toward Cropsey Avenue, perhaps headed toward the waterfront – one of her favorite places.

“We actually even had the Coast Guard team do a whole route down the belt parkway. They haven’t seen anything,” Coyne said.

She has wandered off before, but never for more than a few hours. Now that days have gone by, her grandson said the family is getting desperate.

“Obviously she’s 88, she’s lived a full life, but the fact of not known where she is at all period is frightening,” he said.

Thursday afternoon, family and friends armed with maps and fliers walked around the neighborhood asking anyone if they’ve seen Joyce-Bonsignore.

“It’s horrible. This lady is the type of lady that would help anybody,” family member Tommy Joyce said. “She’s probably one of the best human beings I’ll ever meet in my life.”

The hope is that she’s somewhere safe.

“At this point, we’re hoping maybe a family took her in, maybe an international family and English isn’t their first language,” Coyne said.

But her family can’t help but wonder the worst.

“Now we’re completely accepting the reality that we might never see her again, and it’s getting beyond tragic for me and my entire family,” Coyne said.

This week’s extreme heat is also cause for concern.

Joyce-Bonsignore was last seen wearing a straw hat, red and white shirt and blue pants. Her family said she also wears an identification bracelet that has their contact information on it.