Wedding Anniversary Party Turns Deadly : Crime: The couple returned to the area they grew up in for the celebration. Their son is fatally shot during an argument, and a man is held on suspicion of murder.

A young man was shot to death early Sunday during a fight that broke out at a party celebrating his parents’ 25th wedding anniversary, police and neighbors reported.

Fountain Valley police found Robert Luna Jr., 22, lying on the ground with several gunshot wounds to his chest. Paramedics treated Luna at the scene--the 10400 block of Avenida Cinco de Mayo in the neighborhood known as Colonia Juarez--then took him to Fountain Valley Regional Hospital and Medical Center, where he was pronounced dead at 4:30 a.m.

After searching the area, police arrested Juan M. Hernandez, 28, of Fountain Valley. Police found him hiding in a back yard in the 10400 block of Calle Independencia, about two streets south of the shooting.

A small-caliber handgun believed to have been used in the shooting was found on the ground next to Hernandez, they said.

Hernandez was booked on suspicion of murder and held at Orange County Jail.

Sgt. Lee Pepka said that he did not know what the two men had been arguing about but that the shooting was not gang-related.

Neighbor Ruben Alcala said Luna and his parents had recently moved from Colonia Juarez to Corona. Because they had not yet made new friends, they returned Saturday to the neighborhood they had grown up in to celebrate the wedding anniversary in Mile Square Park.

The party went well until it spilled back into the neighborhood early Sunday morning, and police responded to two calls about neighborhood disturbances.

“First, we heard a lot of commotion,” said Rosalie Sterling of Santa Ana, who was visiting her mother, Susan Mendoza.

“Some girls and guys were arguing and arguing,” Sterling said. “They kept saying the name of that boy (Luna). Then they finally left, squealed out of here. Then an hour later, we heard a lot of commotion and his name came up again.”

Later, she was awakened by two loud bangs. Shootings are rare in the neighborhood, Mendoza said, so she figured it might be cars colliding. But then she heard young people yelling, “Bobby’s hurt, call 911.”

Many families have lived for generations in Colonia Juarez. Once considered a barrio, it has become a mixed neighborhood of new, more affluent homes as well as back-yard shacks.

“When there’s a death like this,” Pepka said, “it affects the whole community.”