The bodies of four people who had been shot to death were found face-down Sunday outside a suburban Southern California home that apparently served as an unlicensed boarding house, authorities said.
Los Angeles police were seeking a motive for the attacks at the house in Northridge, in the San Fernando Valley.
Lt. Terri Brinkmeyer said a 911 call led police to the large house around 4:30 a.m. Cmdr. Andrew Smith said the bodies of two men and two women were found face-down on a side yard of the property.
Investigators were questioning several people who were on the property at the time of the shooting, but no one has been detained or arrested.
Los Angeles City Councilman Mitchell Englander said the house was split into units for rent. He said at least a dozen people lived in the house, which contained several bedrooms, kitchenettes and mattresses on the floor. Englander noted that one bedroom was only accessible through a window.
Syrian warplanes and artillery blasted parts of the capital Damascus and its rebellious suburbs on Sunday, part of what activists described as intense fighting as rebels try to push their way into the center of President Bashar Assad's power base.
In central Syria, a car bomb killed at least 15 people, the official news agency reported.
The fighting over the past few weeks in Damascus is the most serious in the capital since July, when rebels captured several neighborhoods before a swift government counteroffensive swept them out.
The Britain-based activist group Syrian Observatory for Human Rights said fighter jets struck twice in the suburb of Daraya as regime artillery pounded other districts just south of Damascus.
A U.S. Coast Guard member was killed and another was injured when their small boat was rammed by a smuggler's vessel before dawn Sunday off the Southern California coast.
Terrell Horne III of Redondo Beach was pronounced dead after being brought ashore, said Ventura County chief deputy medical examiner James Baroni. He suffered a traumatic head injury, Coast Guard officials said.
The second man was treated for minor injuries. His name wasn't released. Both Coast Guard members were thrown into the water.
Another Coast Guard vessel stopped the smuggler's panga, and detained two suspects.
The amount of heat-trapping pollution the world spewed rose again last year by 3 percent. So scientists say it's now unlikely that global warming can be limited to a couple of degrees, which is an international goal.
The overwhelming majority of the increase was from China, the world's biggest carbon dioxide polluter. Of the planet's top 10 polluters, the United States and Germany were the only countries that reduced their carbon dioxide emissions.
Last year, all the world's nations combined pumped nearly 38.2 billion tons of carbon dioxide into the air from the burning of fossil fuels such as coal and oil, according to new international calculations on global emissions published Sunday in the journal Nature Climate Change. That's about a billion tons more than the previous year.