A 25-year-old man was fatally stabbed early yesterday during an argument inside a Northeast Washington restaurant, D.C. police said.

Police said the trouble occurred about 3:30 a.m. at a Denny's restaurant in the 4400 block of Benning Road NE. The victim, Leon Johnson Jr. of the 2300 block of Pitts Place SE, was pronounced dead less than an hour later at Prince George's Hospital Center.

Travis Wicks, 28, of the 1900 block of R Street SE, was charged with second-degree murder. Police said that Wicks and Johnson were eating at the restaurant separately with friends. Investigators said they believe that an argument erupted over a woman.

An off-duty D.C. police officer working as a security guard at the restaurant broke up the argument and separated the two men, police said. The officer then realized that Johnson had been stabbed, police said.

Johnson's mother, Karen Y. Johnson of Suitland, said her son had been eating with a childhood friend and two female companions.

"There's a hole in my heart that will never be filled," Johnson said. "He was my only son."

Johnson had moved into his own apartment in May, his mother said. The Anacostia High School graduate worked as an apprentice plumber and had just completed the first year of the five-year program. She recalled that her only child loved to cook -- especially spaghetti and German chocolate cake -- and from an early age had prepared elaborate breakfasts for her on Mother's Day.

"I feel sorry for the young man that did this," Johnson said. "He has blood on his hands. He has to live with this for the rest of his life."