OAKLAND, Calif. (AP) -- One of two 4-year-old girls shot in the head in what authorities believe was a gang-related shooting has died.

Datasha Wilson died Thursday night at Children's Hospital in Oakland, Hayward Police Lt. Reid Lindblom said Friday. The condition of the other girl, her cousin, was unknown because the family has asked authorities not to release such information, he said.

"This is a terrible crime," said Lindblom, who is urging members of the public to contact police if they think they may know something about the shooting. "This is two 4-year-old babies who got cut down by gunfire."

The attack took place shortly after 6 p.m. Monday. According to witnesses, three men drove by the house in suburban Hayward and opened fire on a group of adults and children standing in the front yard.

Four or five shots were heard.

The adults weren't hit, but the two little girls and a 3-year-old boy were struck. The boy, who was grazed by a bullet, was treated and released. But the girls were much more seriously hurt; both were admitted to the hospital in grave condition, police said.

"We're pretty sure that this was not a random act. The gunfire was directed at the house," Lindblom said. "This appears to be a gang-related incident."

Neighbors along the street of modest, one-story homes said shootings were not unheard of in the area, but things had been quiet in recent months. A few recalled the children as regular fixtures in the neighborhood, sometimes walking to a nearby store with their grandmother.

Investigators are waiting for results from forensic tests on a car found near the scene that was similar to witness descriptions.

Solving the case has become almost the sole focus of the department, Lindblom said.

"I'm a parent and I think this would kind of play on the sensibilities of anybody that's in a family or had kids," he said. "We really want to catch these guys."