 -- Witness video shows the moment police took down the man accused of opening fire at a birthday pool party at a San Diego apartment complex, killing one and injuring seven others who were "just mere feet from him," police said.

The suspected shooter, identified by officials as Peter Selis, 49, was shot and killed by police at the pool area of the La Jolla Crossroads apartment complex Sunday evening, San Diego police said.

The witness video, filmed from above the apartment complex pool, shows two police officers with their guns drawn, firing across the pool area in the direction of the suspect.

The video later shows those two officers descending on the suspect and five more officers running behind them across the blood-stained pool area.

Police said the eight victims, all adults, were hospitalized. One woman later died. Two victims were in critical condition but they and the other five victims are all are expected to survive, police said.

San Diego Police Chief Shelley Zimmerman said Monday that "in the few days prior to this senseless act of violence" Selis and his girlfriend had split up, and his family described him as distraught and depressed.

Selis, who worked at a car dealership and lived in the apartment complex, allegedly entered the pool area, sat in a lounge chair, and then called his ex-girlfriend, telling her he just shot two people, police said. Selis allegedly stayed on the phone with his ex as he continued to open fire at the victims who were "just mere feet from him," Zimmerman said. Selis allegedly wanted his ex to listen in as he "carried out his rampage," Zimmerman said.

Police said it appears the victims were only targeted because they happened to be at the pool at that time.

Resident Kaela Wong, who was in the pool's Jacuzzi when the shooting happened, said the suspected shooter was sitting under an umbrella in the shade and "didn't draw any attention to himself."

"He had a beer in one hand, and his gun in the other," Wong told ABC News. "I didn't even realize that he had a gun until he started shooting."

Wong said she thought the first shot was actually a bottle of champagne being opened. She soon realized it was gunfire but said she didn't immediately know where it was coming from. People started falling to the ground, Wong said, and she said the suspect sat calmly with his beer, looking at his gun.

Wong said she heard the alleged gunman tell pool-goers they could stay and die or they could leave.