A family's lifetime of work and dreams went up in flames yesterday morning when burglars broke into Mosby's Jewelry Store at 11th and U streets NW, looted the counters of rings, necklaces and other items, then set the place afire, police said.

All that remained in the store, operated by the Mosby family at two locations in the Shaw neighborhood since 1929, was charred and soggy debris. Glass and blackened wristwatches crunched under the feet of fire investigators.

John Mosby, 79, sat on a box in the gutted store yesterday, using a stick to stir patiently through the ashes on the floor, searching vainly for things of value. "It's a terrible feeling. I'm just seeing if there's anything to be had," he said, lifting out a ruined leather wristband. "There's not much left."

Fire officials estimate that the blaze, first reported at 5:27 a.m., destroyed $250,000 worth of jewelry and other goods at Mosby's.

In addition, the fire caused $100,000 worth of damage to the building and to the adjoining Underground Supper Club, 2011 11th St., fire officials said.

None of the contents of the jewelry store was covered by fire insurance, according to Mosby's nephew, Sylvester Coleman, who has operated the store in recent years. Coleman said he could not afford insurance for the store because it is robbed an average of three times a year.

Burglars gained entry to the jewelry store, at 1027 U St. NW, by breaking a window above the front door of a former beauty salon next door at 1025 U St. NW, authorities said.

The burglars then cut a hole in the plaster wall leading to Mosby's, entered the jewelry store and apparently tried to open the large safe in the back, without success.

The burglars removed trays of rings, necklaces, watches, pendants and other jewelry from the glass counters, police said.

The burglars then doused the place with a flammable liquid and set it ablaze, fire and police investigators said.

Flames were shooting out of the jewelry store and the empty apartment above it when firefighters arrived, fire officials said. It took 60 firefighters about 25 minutes to get the blaze under control.

It is not the first time tragedy has struck the Mosby family.

In June 1967, two men entered the jewelry store that Mosby and his wife Louise had owned for 38 years at 1421 U St. NW, asked Mrs. Mosby to show them a watch, and then one of them pulled out a pistol and shot her in the face.

She died almost instantly, as her husband ran to her from a rear room.

Several months later, Mosby moved his store to the present location.

Police and fire investigators removed parts of the burned-out floor near what appeared to be the area where the fire started and sent it to a federal law enforcement laboratory for chemical analysis to determine what started the fire.

The investigators said they had no suspects.