In one incident, a man smeared cake over his girlfriend's face. Police say the couple thought it was funny, but the woman's brother did not.
According to the police report, the brother "took out a knife and stabbed the boyfriend and two other males attending the party".
The boyfriend was taken to hospital suffering from a wound to his abdomen. The second person was stabbed in the hand and back and the third, stabbed twice in the back.
The Los Angeles Times reports that the "alleged attacker fled and is being sought by police".
Another family party ended in an altercation when a 44-year-old man stabbed a 23-year-old in the shoulder over a music dispute. Party-goers successfully caught and held the attacker down until police arrived.
The 44-year-old was arrested on suspicion of assault with a deadly weapon and is booked into county jail. The 23-year-old is currently being treated at a trauma centre.
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