ORINDA, Calif. (KGO) -- The San Francisco Chronicle reports police are looking into whether the Orinda shooting was in retaliation for a quadruple killing in San Francisco's Hayes Valley in 2015.
ABC7 News has learned investigators are checking the backgrounds of the Orinda victims to see if they can help pinpoint a suspect.
Some of the victims had ties to San Francisco as residents. A source tells ABC7 no arrests have been made and no suspects have been identified.
"I'm ripped apart," said Raymon Hill Senior, who was wearing photos of his son, Raymon Hill Jr on a lanyard around his neck.
One of the photos was taken on Oct. 30, the day before Hill Jr was shot and killed at a Halloween house party in Orinda.
"Somebody was upset in there and let the bullets fly," said Raymon, who didn't know his 23-year-old son, a musician who grew up in San Francisco and lived in Oakland, was at the rap event, which was billed as an "Airbnb Mansion Party".
"He was the greatest. He was genuine, loving, loyal. He loved his music."
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It's hard to fathom, but Raymon has lost three of his sons to gun violence. This time, he's angry at police.
Orinda police received multiple noise complaints about the party but did not actually respond to the house until an hour and a half after the first complaint, and two minutes before shots were fired.
"The police didn't do their job that night, the ambulance didn't do their job that night," said Raymon. "Lives could have been saved."
At 8:30 p.m., about two hours before the Orinda shooting, police responded to a home invasion robbery in Lafayette.
Orinda's city manager told ABC7 that their officers were assisting with that call, which delayed their response to the house party.
"It seems like to me they were being lazy, because the whole force wasn't in Lafayette," said Tonya Loftin, who was Hill's Auntie.
To add insult to the injury of losing a family member, Loftin says while she and other grieving families were holding vigil in Orinda Sunday night, people driving by stopped and yelled the n-word and other obscenities.
RELATED: 5th victim dies after shooting at Halloween party at Airbnb in Orinda
"That's what they told us - go back to the ghetto. It's not where you live, it's a respect thing and we didn't get that from them."
On Tuesday, Orinda City Council plans to take up the issue of short term rentals and creating further restrictions to prevent party houses.
San Francisco father loses third son to gun violence at Halloween Orinda party shooting