At least seven others were wounded in the drive-by shootings.
The rampage broke out around 9:30 p.m. The Santa Barbara County Sheriff's Department says it received multiple 911 calls of a suspect opening fire at random. Sheriff's deputies responded and found several victims suffering from gunshot wounds.
As deputies were assisting the injured in the first round of shootings, reports of gunfire in other areas of the college neighborhood were reported.
Deputies were able to catch up with the suspect, six minutes after the initial shooting call was received. The suspect, who was driving a black BMW, allegedly engaged a group of responding deputies with gunfire. An exchange of gunfire ensued, and the suspect fled down Del Playa Drive, eventually slamming into a parked car.
The deputies approached the suspect and determined he was dead from an apparent gunshot wound. It remains unclear if the gunshot was self-inflicted or if the suspect was fatally shot by a deputy.
Deputies later cordoned off approximately nine different crime scenes, including one near a deli and another near a convenience store. A semi-automatic handgun was recovered from the scene.
The Santa Barbara County Sheriff's Department said the rampage was "the work of a madman."
"We have obtained and we are currently analyzing both written and videotaped evidence that suggest that this atrocity was a premeditated mass murder," Santa Barbara County Sheriff Bill Brown said.
Brown said that a YouTube video, posted hours before the shooting, appeared to be linked.
In the video, a young man, sits in the driver's seat of a car as he promises "retribution" and discusses his "loneliness, rejection and unfulfilled desires."
"Girls gave their affection and sex and love to other men but never to me," he says. He adds that it'll be his last video.
"I'll take to the streets of Isla Vista and slay every single person I see there. All those popular kids who live such lives of hedonistic pleasure while I've had to rot in loneliness for all these years. They've all looked down upon me every time I tried to go out and join them," he says. "They've all treated me like a mouse, well now, I will be a god compared to you."
Police haven't confirmed whether the person who posted the video or man in it is the suspect.
Deputies say the suspect has been identified. His name has not been released pending the ongoing investigation.
Isla Vista is home to 23,000 people. The area, located next to UC Santa Barbara's campus, has a reputation for excessive partying.
The victims' identities were not immediately released pending notification of kin. The injured were being treated at Santa Barbara Cottage Hospital for gunshot wounds and traumatic injuries, including at least one person who underwent surgery for life-threatening injuries.
The investigation is ongoing. The Santa Barbara County Sheriff's Office is being assisted by the UCSB Police Department, the California Highway Patrol, the Santa Barbara Police Department, investigators from the Santa Barbara County District Attorney's Office, California State Parks and criminalists from the Department of Justice crime lab.
Anyone with any information was urged to contact the Santa Barbara County Sheriff's Tip Line at (805) 681-4171.
The Associated Press and ABC News contributed to this report.
