BURBANK, CALIF. — At about 9:30 a.m. on Dec. 11, Julie Tran Nguyen was cleaning her house when she heard a loud pop. Flat tire, she thought, and continued cleaning. Then she heard the side gate slam shut. From her window, Julie watched a thin Asian man wearing dark-colored clothes and a baseball cap hurry to a dark sport utility vehicle. After fumbling with the keys, he hopped in, backed out of her driveway and sped off northbound on Lamer Street.

That’s strange, she thought. She opened the back door of her house and peered out. Nothing unusual. She started to close the door when she looked to her right. Her son, Man Nguyen, was lying by the side gate, blood gushing from his head.

Burbank police Detective Chuck Howell arrived at 1224 N. Lamer St. at about noon. His officers had already set up the crime scene and had begun documenting evidence. The victim was found on his back, near the wrought-iron metal gate, a 9-millimeter shell casing about four feet from his body, Howell said. Man Nguyen, 31, died from a bullet wound to the left side of his head.

Police searched Man’s bedroom and found more than five pounds of neatly packaged marijuana in the closet. Stuffed into a green backpack were methamphetamine, cocaine and ice. Also on the closet floor was a blue notebook with the first names of people who owed Man money, Howell said. In a jewelry box atop a dresser was more meth, about $680 in cash and a set of keys, one of which opened the lock to a storage room in Van Nuys, where police found more marijuana.

Howell questioned all members of the Nguyen family. Mike, Jimmy and Man all lived with their mother, Julie, whose house, according to police, was laid out as more of a family compound than a single-family dwelling. Jimmy and Julie stayed in the front house; Mike and Man each lived in separate units in the back. The sole means of entrance to Mike and Man’s residences was through the wrought-iron metal gate.

Man’s brothers knew that he made his living as a drug dealer, but he rarely made trades from home, they said. Mike, who used to deal drugs with Man, told police that they agreed to always keep the gate locked, double-bolted. Man would only let those whom he “absolutely trusted” back there, Mike said. Lately, aside from family, he had seen three people visit Man: Peter Li, Mike Pak and Steve Kim.

At about 7 p.m., Dec. 10, Mike, walking to his own unit, passed his brother’s residence and saw through the sliding glass doors his former friend Steve Kim, on Man’s couch. He kept walking.

Mike and Kim knew each other from their high school days and had been good friends, but they had since had a falling out, Mike told police. Kim, 26, a former member of the Korean hip-hop group Uptown, had known the Nguyens since 1990.