Police in the central California city of Fresno were searching Monday for suspects and trying to determine a motive for the killing of four people at a backyard party and the wounding of six as dozens were watching football on TV.
Fresno Police Lt. Bill Dooley said "unknown suspects" sneaked into the backyard at about 6 p.m. Sunday and fired into the crowd.
Fresno Deputy Police Chief Michael Reid told the Fresno Bee newspaper and the KSEE/KGPE TV stations that 10 people were shot and that three were found dead in the backyard. A fourth person died at the hospital. Six others are expected to survive and were recovering at a hospital.
The victims were men ranging in age from 25 to 35, Reid said.
"What we do know is that this was a gathering, a family and friend gathering in the backyard," Dooley said. "Everyone was watching football this evening when unknown suspects approached the residence, snuck into the backyard and opened fire."
Fresno Police spokesman Lt. Mark Hudson did not immediately return email and phone messages Monday seeking additional comment.
The victims were taken to Community Regional Medical Center in critical condition, and some are now in stable condition, the TV stations reported.
About 35 people were at the party when the shooting began, Reid said.
"Thank God that no kids were hurt," he said.
No one had been taken into custody and authorities said there was no immediate indication that the victims knew the shooter or shooters. Police were going door-to-door in search of surveillance video that might help them track down the suspects.
Agents from the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives field office in San Francisco responded to the shooting, the Bee reported.
Other shootings have happened recently in the same neighborhood, leaving neighbors frightened, they said.
Choua Vang told the Bee that his neighbor's house was shot at last week and that he feels unsafe outside after dark.
"We're thinking about moving out of the neighborhood," he said. "We don't know how many more shootings there will be."
It was at least the second fatal gun attack Sunday in southeastern Fresno, the Bee reported. A man in his 20s was shot to death early Sunday at a home in another part of the city. Police have not said whether the incidents could be connected.
Sunday's Fresno shootings came after two other mass shootings in California.
Last Thursday, a 16-year-old student at a Southern California high school in the city of Santa Clarita outside Los Angeles shot and killed two classmates and wounded three other teens before shooting himself in the head. He died the next day.
And on Saturday, police in San Diego said a husband shot and killed his wife and three of their sons before killing himself. A fourth son wounded in the shooting was on life support on Sunday, family members said.