INDIO — A 45-year-old man briefly spoke to his killer before the gunman took a step toward the victim, aimed the weapon at his head and pulled the trigger outside a Desert Hot Springs supermarket, court documents filed at the Larson Justice Center show.

Anthony Raymond Magdaleno, an 18- year-old Los Angeles County resident, is accused in the Oct. 10 shooting death of Chi-Lu “Tony” Chen outside the Vons supermarket on Palm Drive.

Magdaleno, a self-admitted gang member in Hawaiian Gardens, was arrested Wednesday in Los Angeles County, according to Sgt. Dan Bressler of the Desert Hot Springs Police Department.

A witness, who was sitting in the Vons parking lot on Oct. 10, told police Chen walked through the lot to the front of the store and was immediately confronted by his shooter, according to a declaration in support of an arrest warrant.

The witness said the victim and gunman began talking, and “it appeared to be an unpleasant conversation. However, they were not physically involved nor did it appear to be anything protracted or violent,” according to Bressler, who prepared the document.

Bressler said he did not know what was said.

When Chen turned away and took a step toward the sliding door to enter the store, the gunman made a remark and Chen turned to respond, Bressler wrote.

“As he turned, (the gunman), who had taken a step or two toward victim, quickly raised his right arm, pointed a handgun at victim's head and pulled the trigger,” the sergeant wrote.

The witness reported hearing the shot and seeing the muzzle flash before the gunman fled on foot toward a McDonald's restaurant west of the supermarket, according to Bressler.

The exchange happened sometime within about a 50-second window, according to grocery store surveillance footage that police say shows the gunman walking by before the shooting and running back by seconds later.

The sergeant said police have not determined a motive for the slaying.

Another witness reported that a young man came to his home and asked to use the phone inside not long after the shooting, according to the document.

The man said the teen told him he was a gang member from Los Angeles and gang members from the “Inland Empire” gang had just confronted him and began shooting at him, Bressler wrote.

The young man asked to use a phone and dialed a number, but there was no response and he asked for a shirt so he could escape, according to the sergeant.

The man refused, but offered to give the young man a ride and dropped him off in the area of Cactus and Buena Vista, where there is a known “safe house” for gang members, Bressler wrote.

Police tracked down the phone number that was dialed, which was traced back to Magdaleno, who lives in Hawaiian Gardens, Bressler wrote.

Chen had recently moved to the Coachella Valley to work in sales and marketing at the Agua Caliente Hotel on Palm Drive, across the street from the supermarket.

Magdaleno, who is being held in lieu of $1.5 million bail, is set to be arraigned Monday afternoon.

Desert Sun reporter Kate McGinty contributed to this report.