He was also wearing pants sprayed with blood and told police that he had stabbed her with a knife, Lugo told jurors.
A large knife with its tip missing was found in the kitchen sink at Susan Kim's home, Lugo said as she displayed a photograph of Susan Kim's bloodied body.
Neighbors saw him speeding away about 3 or 4 p.m. that day from the home in a white Lexus, Lugo said.
Soo Duk Kim was arrested Dec. 17 in a Koreatown motel, less than 12 hours after Susan Kim's death.
Soo Duk Kim's attorney, James Bisnow, told jurors during his opening statement that his client had suffered from a long battle with mental illnesses, describing him as a "schizoaffective disorder bipolar-type."
After being arrested for Susan Kim's death, he attempted suicide three times, Bisnow told jurors.
"He was in a psychotic frenzy…. He was in the throes of this episode," Bisnow said.
Soo Duk Kim had apparently grown angry at Susan Kim after she took his house keys and told him to return to Korea, Lugo told jurors. An argument ensued, and he allegedly told police that he "grabbed her head and hit it against the wall."
Her daughter, Jane Moon, testified Tuesday that her mother and Soo Duk Kim had been arguing since the morning of her death.
She also testified that Soo Duk Kim, who was unemployed, talked to her only when her mother was nearby.
"I don't think I had a real conversation with him," she said. "I think he was just socially awkward, but there was nothing too bizarre or nothing too odd."