At Least 20 Die in County in a Weekend of Violence : Crime: The victims include a 4-year-old boy and a girl, 16, in separate incidents.

A weekend of violence left at least 20 people dead and more than a dozen others wounded countywide, authorities said.

Sheriff’s homicide detectives were investigating the apparent murder of an elderly woman in La Canada Flintridge.

Neighbors heard gunshots and called deputies, who found the unidentified woman dead inside her home in the 600 block of Durwood Drive shortly before 7 p.m. Sunday, Lt. Robert Flores said. Deputies held a man and woman found hiding in a side yard for questioning, Flores said.

Long Beach police were investigating two unrelated stabbing deaths Sunday evening.

Sheriff’s deputies were investigating the death of woman whose body was found about 6 p.m. Sunday in a pickup truck on Las Virgenes Road in Malibu.

Compton detectives were investigating the death of an unidentified young man in the 2600 block of North Parmelee Avenue about 8:30 p.m. Sunday. Police did not immediately know how the person died, “but there appears to be some trauma to his head,” a spokesman said.

In Inglewood, Jesus Zubia, 24, was booked for investigation of murder after his son was shot at their home, although investigators believe the shooting was an accident, Police Sgt. Percy Roberts said.

Zubia told officers he thought his .38-caliber revolver was unloaded Friday night when he showed it to his two sons, ages 4 and 7, and repeatedly pulled the trigger. The gun fired once, and the 4-year-old was shot in the head.

Meanwhile, police hunted for the killers of a cab driver whose body was dumped on a street near downtown Los Angeles. Stanley Kolski, 53, was found shot in the head Friday evening, police said.

Elsewhere, a man who refused to share some cocaine was stabbed to death Sunday morning in Venice, and in the east county community of Walnut a man was found shot to death outside his apartment building, authorities said.

Seven people were wounded in an apparently gang-related drive-by shooting near Los Angeles City College.

A 16-year-old girl was fatally wounded shortly after 1 a.m. Sunday as she rode in a car with friends in the Willowbrook area, sheriff’s deputies said. People in the car had exchanged “gang words” with pedestrians, who opened fire, officers said.

Shirley Sandoval, of Los Angeles, died at a nearby hospital. A male suspect, whose name was not released, was in custody for investigation of murder, officers said.

A drive-by shooting claimed the life of a 19-year-old Los Angeles man early Sunday after he was struck by gunfire from a passing car on West 22nd Street.

In Hollywood, one man was killed and another injured in an apartment window after exchanging taunts with some people on the street, one of whom pulled a gun, police said. There were also shooting deaths at a Highland Park intersection and near a Los Angeles hamburger stand.

Six other people died in weekend violence previously reported by The Times.