Detectives said the victim, identified only as a 29-year-old man, had a gathering at his apartment in the 8700 block of Magnolia Avenue on Friday evening. Shortly before 1 a.m., he was attacked by five people in his bedroom.
Riverside police said the man was punched and kicked during the assault. He was also stabbed by one of the suspects.
The motive for the alleged assault was unclear.
Responding to a 911 call, police arrived to the man's home and found him being assaulted by a woman.
The victim was transported to a hospital, but succumbed to his injuries hours later.
Peter Zamora, 21; Desiree Huerta, 42; Samuel Zamora, 18; a 17-year-old boy and a 16-year-old boy - all Riverside residents - were arrested for murder. The names of the teenage suspects were not released because they are minors.
Stephanie Vargas, 26, of Riverside, was arrested for aiding a felony.