DETROIT - After losing thousands of dollars in a day of gambling at Detroit's brand-new casinos, off-duty police Sgt. Solomon Bell tried one last high-stakes hand of blackjack.

He lost.

The decorated officer abruptly stood up from the table, cried out "Noooooo!," drew his gun and put a bullet in his head as other gamblers scrambled for safety.  The death--believed to be the first suicide inside a U.S. gambling hall--has highlighted concerns about casino gambling in a city pinning much of its hopes for revival on three new casinos.

Bell's death on Wednesday was shocking to people who knew him.  He joined the Oak Park force about 12 tears ago and rose from uniformed patrol officer to investigator, sergeant and patrol supervisor. 

His service record was unblemished.  In 1988 and 1990 he got merit awards for arrests in stolen-vehicle cases, said Bob Bauer, the department's deputy director. 

"I just describe him as a good guy," Bauer said.  Away from his $ 63,675-a-year job, the unmarried Bell kept mostly to himself and took meticulous care of his house in nearby Southfield.  He owned a 1995 Cadillac Seville and liked to roller-skate. 

Co-workers said they knew he occasionally gambled, but never saw signs of a problem.  Then, on his day off, authorities said he lost $ 15,000 to $20,000 at the MGM Grand Detroit Casino, which opened in July and the 6-week-old MotorCity Casino.

At MotorCity, spokesman Jack Barthwell said, Bell tried various blackjack tables in the high-stakes VIP room before losing roughly $4,000 on a single hand at a $100-minimum game.

Bell then pulled his gun and fired a shot into his temple so abruptly the few players and about 20 casino workers on the fourth floor had no time to intervene, Barthwell said.

Another potential crisis was averted yesterday, when a 37-yerar Detroit firefighter threatened to kill himself at the MGM Grand Detroit while playing blackjack.

Police alerted by the dealer, took the man into custody for treatment.  Carol O'Hare, executive director of the Nevada Council on Problem Gambling, said she knows of no previous suicide committed inside a U.S. Casino.