LONG ISLAND N.Y. (PIX11) — The sister of 38-year-old David Forbes, who has developmental delays and a history of making bomb threats, was desperate to find him Saturday, after he left the family home in the early hours of July 5th.

“He resides in Massachusetts at a residential school,” Bonnie Forbes, the missing man’s sister, told PIX11 News.  “He was home for a week-long visit and he was supposed to go back July 5th.”

The sister said David Forbes has been living at the out-of-state residential facility for more than a decade and didn’t like the restrictive environment.  Yet his sister said Forbes had made friends at the Judge Rotenberg Center in Canton, Massachusetts, getting a job there, going bowling, along with excursions to parks and movies.

The enduring problem, though, has been what Bonnie Forbes called an “attention-seeking disorder.”

“He’s sometimes made false bomb threats,” Bonnie Forbes noted. “One time he e-mailed a threat to an NCIS base down south.”

Bonnie Forbes said another time, swat teams arrived at the mother/daughter house where she lives in Coram, NY because he called and said he had killed his own family.  Meantime, we were all sitting around the table laughing at the time.

The sister added her brother had no history of violence, but the false threats continued to cause the family grief.

The sister said a Coram neighbor saw David Forbes outside the family home early Wednesday morning near the mailbox, around 12:30 a.m.  Another neighbor saw him outside around 4:40 a.m.

Bonnie Forbes said her brother stole her credit card and some cash before he left.  She canceled the card, but police are trying to track the card through failed attempts to use it in Manhattan.

The last attempt to use the card was 10:24 a.m. Friday at a vending machine near West 59th  Street.

“We think he may be in Central Park,” Bonnie Forbes said.

Suffolk County police sought the assistance of the NYPD and learned Forbes, a diabetic, had been treated at Mount Sinai West Hospital in Manhattan within a day of his disappearance.  He was released on Thursday, July 6th, and the hospital cited HIPPA (privacy) laws when the family sought details of his treatment.

The Forbes family is afraid he may do something that puts him in more danger.

“One time, he had a water gun, and he told somebody he wanted his car keys,” Bonnie Forbes said.

The family said it’s been dealing with the missing man’s tendency to take off for a long time.

“We’re not sure why.  It’s called elopement,” Bonnie Forbes said.  “One time, he left with no shirt and no shoes on.  He was actually found under a conversion van and had to be treated for hypothermia.”

Anyone who spots David Forbes is urged to call 911 or the Suffolk County Police Department at (631) 854-8614.