Brown told CNN on Sunday that investigators are close to having a "pretty clear picture of what happened."
The first three killed Friday were male stabbing victims in Rodger's own apartment Brown said Saturday. Then, at about 9:30 p.m., the shooting rampage began.
The Santa Barbara sheriff's office said Sunday that the victims were all UC Santa Barbara students: 20-year-old Cheng Yuan Hong and 19-year-old George Chen and 20-year-old Weihan Wang.
Hong and Chen are listed on the lease as Rodger's roommates. Investigators were trying to determine whether Wang was also a roommate or was visiting the night of the killings.
The shooting victims were identified earlier as Katherine Breann Cooper, 22, Chrisotper Ross Michael-Martinez, 20 and Veronika Elizabeth Weiss, 19.