San Diego police say there is "zero" evidence a white man who shot at six African American people and a Latino man, killing one, was racially motivated.
Instead, police say 49-year-old Peter Selis was distressed over a recent break up and financial trouble.
Selis was shot dead by police after he opened fire at a pool party held at a luxury San Diego apartment complex and was on the phone to his former partner during part of the rampage.
Police chief Shelley Zimmerman said there was "zero information to indicate race played a factor in this terrible and horrific crime", The Los Angeles Times reports.
The shooting happened shortly after 6pm on Sunday (local time) after Selis, a car mechanic, walked to the pool an initially sat in a lounger.
That's where he fired his first shot and then began moving around the pool, Ms Zimmerman says.
Police responded in force, with 20 officers and a police helicopter arriving at the scene around seven minutes after being called to the scene.
Selis shot at two police sergeants and two patrol officers when they arrived. They returned fire, killing the gunman.
All the victims were adults; four black women, two black men and a Latino man. One of the women died in hospital, but her name has not yet been released.
Ms Zimmerman says the others are expected to survive their injuries, some of which were critical.
One witness told news channel KFMB-TV he saw Selis with "his beer in one hand and his gun in the other" after hearing screaming and gunshots around 6pm.
Official documents said Selis was more than US$100,000 in debt and when listed the complex as his address when he filed for bankruptcy in 2015, the LA Times reports.