The son gave his father a gun a few weeks ago, after someone broke into the family grocery store.
The father, waking up Saturday to what he thought was a second break-in, fired it nine times.
One shot caught the son in the chest and killed him. Moo Yul Sung was 27.
Two police officers heard the shots. They were standing in front of Johnston's Grocery store at the corner of Greenmount Avenue and East Preston Street, waiting for Moo Yul Sung to go in and turn off the burglar alarm that had brought them there.
It was 4:25 a.m. The officers had already checked to make sure there was no burglar.
But Gil Nam Sung, the father, didn't know that.
The two officers heard a single shot, then a volley of shots and a man screaming in a foreign language. They rushed to the back of the three-story building that houses Johnston's.
At the top of the steps to the second floor, Gil Nam Sung was sitting with his son cradled in his arms. The blood was spreading thickly across the young man's shoulder and arm.
The father lifted his right arm. The officers saw he was holding a gun. He dropped the gun and stood up. His son's body, covered in blood, rolled down the steps.
An ambulance arrived. Moo Yul Sung was declared dead.
Evidence at the crime scene included nine spent cartridge casings. The door to the second floor, where the father had spent the night hoping to prevent a burglary, was still open.
The father was taken for questioning. But pending further investigation, police said yesterday, he will not be charged.
"An accident isn't a crime," said Baltimore police spokesman Dennis S. Hill.
That doesn't make much difference to Gil Nam Sung, 55.
His daughter, Hwa, walking out of the Woodlawn apartment house where she lived with her brother, said in Korean, interpreted by a friend, that the family for now does not wish to talk about the incident.
The father and daughter were wearing black. The father walked with bowed shoulders and said not a word. The funeral is set for Wednesday.
Last October, another man died at Johnston's grocery store. It was Moo Yul Sung's uncle, Agapito "Pete" K. Cho.
That time, it was a man robbing the store who had a gun. Mr. Cho was shot once in the head.
"The father, he was panicked," said Kyu Kim, who, with his elderly parents, runs Avenue Liquors across the street from the grocery. "His family member got killed. There'd been a few break-ins. He panicked."
Mr. Kim has been doing business in the neighborhood of boarded-up buildings and littered streets for about four years. The Sungs, he said, have been there about two years. The elder Sung's wife died last summer, he said. He thinks there are two brothers still in Korea.
At Avenue Liquors, customers are separated from the Kims by a floor-to-ceiling metal grille. Money and goods are exchanged through revolving plexiglass-cylinders. A buzzer releases the lock on the inside door.
The elder Mr. Kim, 64, said there have been attempted break-ins at his place, too -- and that he also keeps a gun.
Customers walk in asking for cigarettes, small bottles of liquor, six-packs of beer. Some are drunk. "Hi, papa-san," one calls, waving cheerfully at Mr. Kim, who smiles and nods.
Mr. Kim said he saw his young neighbor and countryman, Moo Yul Sung, often.
"He come here every night," Mr. Kim said. "Young," he says, shaking his head. "Young."
"The father," Mr. Kim says, crumpling his face to mimic crying, "all day, all day."