Six officers eventually responded. A surveillance camera near the bus depot was recording.
Prosecutors allege former Fullerton officer Manuel Ramos turned a routine encounter with the 37-year-old mentally ill homeless man into a deadly beating. Ramos's attorney, however, says Ramos was doing his job, faced with an uncooperative suspect.
Ramos was charged with second-degree murder. Jurors saw photos of his injuries.
Forensic specialist Scruggs said that when she arrived, Ramos told her, "He [Ramos] was in the fight of his life, he had never had anyone fight him like that."
Scruggs says Cicinelli, who is charged with involuntary manslaughter, suffered a thumb injury. She testified "He [Cicinelli] was also kind of shaken and he explained to me this guy would not stop fighting. He would not stop fighting. ... He tased him a couple of times and had no effect."
Video shows Cicinelli using his Taser to hit Thomas's head.
Thomas's father, Ron, listened as a paramedic testified that he was first directed to treat an officer's minor injury, then happened to notice Thomas lying unconscious in a pool of blood.
"Nobody at all from law enforcement directed them to Kelly. Kelly is dying in the gutter," said Ron Thomas.
Photos shown at a previous hearing show Thomas's facial injuries. At the scene the paramedic said Thomas was breathing but his nose and mouth had to be cleared of blood. Halfway to the hospital, his heart stopped. Five days later, he was removed from life support and died.
Ramos and Cicinelli have both pleaded not guilty.
Testimony continues Thursday.