William A. Keefer didn't talk much about work when he went home to Bladensburg after a night of driving his cab through District streets. He just told his family it was getting more dangerous.

Keefer, 64, started as a cabdriver here during World War II when it was one of the best paying jobs available in a city swelled by war workers.

But in recent years, Keefer, who liked to drive at night because there was less traffic, had become increasingly concerned about his safety on the streets of his native city, his wife recalled.

A few minutes after midnight yesterday, D.C. police found Keefer slumped behind the wheel of his Dial Cab Co. taxi at Sixth Street and Maine Avenue SW with a bullet wound in the back of his head.

He died about half an hour later at George Washington University Hospital.

"He always talked about how terrible it is lately because he was working in the District," said his wife, Ruth. "He wished he could get out of it."

"He liked it," she continued. "He was his own boss. I believe that's what they drive cabs for. He was getting tired of it though, because it started to get rough in the District."

Police said they believe Keefer was killed during a robbery, apparently by a gunman who ran from the scene immediately after the shooting.

Investigators said they have no suspects in the killing but that they are studying Keefer's trip sheets in an attempt to learn where he picked up his last passenger.

Keefer was the second D.C. cabdriver slain during an apparent robbery this year. Douglas R. Thornton, 42, who also drove a Dial cab, was struck in the head with a blunt instrument and left to die in an Arlington parking lot in January.

Ruth Keefer, 63, said yesterday that although her husband's earnings had decreased as the years passed, he stayed behind the wheel.

"He just took it from day to day," she said."He was just very lucky all those years out on the street. Everybody thinks it couldn't happen to them, but it did."

She said her husband had been robbed only once before during his more than 40 years as a cabdriver.

William Keefer, who was born in the District but moved to Bladensburg more than 10 years ago, was a "family man" who enjoyed airplanes and immersing himself in nature, his wife said.

The couple's only child, Ruth Ann, 27, said what she'll miss most about her father is "everything." "We had such good times together, the whole family," she said.

Keefer's death led Dial Cab Co. president Daniel Smith and other drivers to criticize city protection of hackers.

Smith said the city "really has no concern for cabdrivers" because there are no requirements for protective shields between drivers and passengers and two-way radios that drivers can use to call for help.

Smith said it is too expensive for individual companies to put in these improvements in the absence of city regulations requiring them in all taxis.

Keefer's cab had no radio, Smith said. For those drivers with radios, Smith said, Dial has a system of emergency signals that alert dispatchers, other drivers, and ultimately the police, if a driver is in trouble.

Several drivers in the fueling and repair station Dial shares with a number of other companies alleged yesterday that police departments in surrounding counties give greater protection to cabdrivers than D.C. police.

"Those guys in the county don't have the problems we have," said a driver who asked not to be identified, "because they just say 'boo' " and police respond quickly to trouble reports, make sure the driver is paid, and if he is not, they arrest the passenger.

Another driver said that if D.C. police arrest a fare he's had trouble with, "I'll bet you $50 to a doughnut, he'll beat me back over here . . . on his own recognizance."

Lt. James Waybright of the D.C. police robbery squad, said, "As a general rule, cabdrivers are very vulnerable.

"It's like throwing the dice. If you pick up enough people, sooner or later you're going to pick up . . . someone who pulls out a gun and robs you," he said.

There have been about 53 robberies of drivers this year, Waybright said.