A 68-year-old Silver Spring woman described by family and neighbors as "quiet and generous" was shot to death yesterday, apparently as she was washing the inside of her living room window.

Montgomery County police said Abraham (Al) Blanco, 68, returned home at about 11:30 a.m. from a doctor's appointment and found his wife, Rose, lying over the back of the living room sofa in front of a bay window. She had been shot in the back of the head.

Police said they believe the woman was shot from inside the house, at 2301 East-West Hwy., since a bullet went through the bay window, spreading glass fragments through a tree's top level outside, and landed on a lawn across the road.

Police said no motive for the slaying has been established. There were no signs of forced entry, they said, and nothing apparently was taken from the home. The can of window washer Mrs. Blanco had been using was still standing on the window sill, police said.

Blanco told police that fron door was open when he returned home and that it had been shut when he left.

Police are looking for a silver-bodied truck with a red cab occupied by two men that was seen in the neighborhood, according to Cpl. Phillip Caswell, police spokesman Larry Weiss, who was painting a house across from the Blanco home yesterday, told police he had seen a delivery truck of that description drive around the side of the Blanco home.

Weiss said he though he saw "one or two men" get out of the truck, but did not see them enter the Blanco house or leave the neighborhood.

Police said they had not determined what type of gun fired the fatal bullet, but it probably was "more than a .38 caliber" weapon, Caswell said.

Abraham Blanco operated White's dry goods store at 14th Street and Columbia Road NW. for 25 years until the store was burned out in the 1968 riots, according to the family.

Mrs. Blanco's slaying yesterday was the latest of a series of tragedies for the Blanco family. The Blancos' eldest daughter died as a result of a fire in 1973 and their only son died only a month later, according to a family member. A daughter who lives in Potomac and six grandchildren survive.

The Blancos' two-story, split level home is in the Rock Creek Forest area of Silver Spring a short distance from Chevy Chase.

The upper-middle class neighborhood, with homes selling for $60,000 and $70,000, according to one resident, has been plagued by burglaries over the past few years. The Blanco home was burglarized several years ago, according to neighbors. Police said two homes across the street from the Blanco house had been burglarized within the last years.

Friends and neighbors described the Blancos, who were married in 1929, as devoted to each other and to their synagogue, Tifereth Israel at 16th and Juniper Streets in the District of Columbia, Blanco was the voluntary sexton of the temple and his wife was regarded as "the grandmother of the congregation," a family friend said.

"She (Mrs. Blanco) was always surprising kids on the Sabbath with candies and baked goodies . . . All the families in the synagogue were like children to her," recalled Steve Feigin, a member of the Tifereth Israel congregation.

Some residents of the Blanco's neighborhood told a reporter yesterday they have been "scared to death" as a result of the string of burglaries and yesterday's shooting and were thinking of moving out.

"But where would I go? It's not safe anywhere," said one woman who had lived in a house across the street from the Blanco for 20 years.

"I guess I could put bars on my windows," said another woman, who live alone.

The neighbors said they feared to have their names published in the newspaper.