An unidentified gunman shot and killed five people in a series of shootings in Southern California before taking his own life, police said.
Donny Youngblood of the Kern County Sheriff's Department said deputies were called to the trucking business after reports of shots being fired at 17:20 local time (00:20 GMT).
Along with his wife, the attacker killed a man at a trucking company in Bakersfield. He then shot his wife and another man - before he ventured into a nearby neighborhood and shot a married couple.
Another person arrived on the scene and opened fire on the gunman.
The gunman then went to a home where he shot two people, the sheriff continued.
The gunman then wandered toward a nearby road and approached two people near a home.
The suspect then carjacked a vehicle with a woman and child inside.
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He called on the two men to contact the media and "tell about themselves" - which they then duly did. They spent New Year's Eve in Switzerland and have been to Vienna, the pair said.
Except for the gunman's wife, there was no immediate word on how the victims might have been related.
Sheriff Youngblood later told reporters his team was carrying out an investigation into the mass shooting.
"Obviously there's some type of situation that caused the husband to be extremely upset", Youngblood said, adding that he's confident of a connection between those involved. The deputy who confronted the man was wearing a body camera.
It was also not known what had sparked the shootings, which saw all six people die in a short amount of time, Mr Youngblood said.
About 30 people saw the shootings and were being interviewed by deputies, Youngblood said.
The Kern County Sheriff's Office held a press conference Wednesday night and said the investigation is ongoing, but investigators are confident the shootings are connected.
He shot both of them dead, police said. "This is highly unusual", he said.