Maurice Lopez of Hollywood said he woke up to the sounds of an argument.
"It was very heated. It woke me up," Lopez said.
Authorities said they received multiple 911 calls of shots fired in the 6500 block of Hollywood Boulevard at about 3 a.m.
When police arrived, they found a 25-year-old woman with several gunshot wounds on the third floor. She was declared dead at the scene.
Neighbors said in the midst of the couple's fight, the girlfriend left the apartment to get away, and then her boyfriend shot her several times in the hallway.
According to LAPD Lt. Robert Binder, a quick investigation led officers to a suspect. The man barricaded himself in his apartment.
Residents in the apartment building along the Hollywood Walk of Fame were evacuated, and Hollywood Boulevard was shut down in the area during the standoff.
Detectives said the incident ended peacefully, with the suspect taken away in an ambulance. Police say the suspect sustained minor injuries at the time of the arrest.
No shots were fired by police, and no one else was injured in the incident. The female victim's identity has not been released.