The charge against the man who allegedly gunned down a Silver Spring resident as he walked his dog Saturday was upgraded to first-degree murder yesterday, according to a spokesman for the Montgomery County state's attorney.

Police said a masked Shawn Anthony Bowman had just taken $2,200 at gunpoint from the Safeway on University Boulevard West, when he encountered Luis Sequeira, 47, near his Silver Spring home. Bowman shot Sequeira three times--once in the eye and twice in the torso, police said. Sequeira died the next day.

Bowman, 32, of Forestville, also was charged with armed robbery and the use of a handgun in the commission of a felony, said John McLane, spokesman for the prosecutor. He was being held yesterday without bond in the Montgomery County jail. Another bond hearing was scheduled for today.

Bowman, whose criminal history includes a 1993 conviction for bank robbery in U.S. District Court in Baltimore, tried to escape from the scene in a white pickup truck from District Cablevision, where police said he was employed.

Earle Jones, general manager of District Cablevision, declined to talk about Bowman. But he said the company requires criminal background checks, drug testing and references for all employees. Jones said Bowman was not authorized to take the company truck on Saturday, but would not say whether he was working that day.

"It certainly is not our policy for our customers to be harmed in any way," Jones said. "We're still awaiting the outcome of the investigation. Certainly we feel very badly about what happened."

Court records show that Bowman has a criminal history that includes charges of bank robbery, assault with intent to rob, assault and battery, robbery with a deadly weapon, simple assault, unlawful entry and possession of cocaine.

The Montgomery County judge who sentenced Bowman after his most recent conviction, for the 1993 armed robbery of a Silver Spring Pizza Hut, gave him a five-year suspended sentence and three years of probation.

According to the police account of that late-night robbery, Bowman talked his way inside the restaurant, saying he needed to pick up a carry-out order. Once inside, he covered his face with a scarf, displayed a gun in his waistband and forced the manager to give him $1,129 from the safe and cash drawer.

According to court documents, Bowman pleaded guilty to one count of robbery in the case, and Montgomery Circuit Court Judge Martha G. Kavanaugh dismissed the handgun charge, giving him three years of supervised probation.

In 1997, Bowman sought through court filings to have some modification of the probation he was serving for the Pizza Hut robbery, citing conflict with his job at District Cablevision. "Mr. Bowman is concerned he might lose his job if he is required to continuously miss work hours due to his present reporting requirements," his lawyers wrote, asking that Bowman be allowed to report to his probation officer by phone instead of in person.

It was not clear from the records whether the modification motion was granted.