D.C. Police cordon off the scene in the 3300 block of Q Street where an elderly couple were stabbed at their Georgetown home. (Nikki Kahn/The Washington Post)

An 88-year-old Georgetown man was stabbed to death in his home Sunday morning and his 81-year-old wife suffered numerous knife cuts in what police said was an apparent domestic altercation between the couple and their son, who reportedly was mentally ill.

The son, Bradford Nelson ­Elliott, who is 56 and lived with his parents, was hospitalized after the incident with injuries to his hands, police said.

Police spokeswoman Gwendolyn Crump said Sunday night that he had been charged with first-degree murder while armed.

The Elliotts — Le Roi, who was killed; his wife, Vaughan; and Bradford, one of their two sons — lived in the 3300 block of
Q Street NW, police said. They said Vaughan Elliott, bleeding from knife cuts, called 911 about 6:30 a.m. to report the altercation.

When uniformed D.C. police officers arrived at the house, Bradford Elliott answered the front door with blood-soaked hands, police said.

“The officers obviously got him medical treatment but also made a decision to arrest him,” Assistant Police Chief Patrick Burke said.

Le Roi Elliott, who suffered an undetermined number of stab wounds, was found unconscious in an upstairs bedroom and was pronounced dead at a hospital, police said.

They said his wife was hospitalized in stable condition.

The couple had lived in the house, valued at just over $1 million, since 1985, according to real estate records.

Evidence taken from the home by detectives included a knife that police believe was used in the attack, Burke said.

The couple’s other son, Reade Elliott, who lives in Loudoun County, arrived at the house early Sunday afternoon and spoke with homicide detectives there. Like others interviewed by police, Reade Elliott described his brother as having a history of mental illness, one detective said. The specific nature of his problem was not immediately clear.

“While we’re continuing to investigate what occurred,” Burke said. “The situation appears to mental-health related.”

Vaughan Elliott’s father, the late Lorenzo S. Winslow, was an architect who designed many features and additions to the White House.

Le Roi Elliott “was an extraordinarily nice man,” said a neighbor, 96-year-old Page Wilson. “I knew he had two sons, and I knew one of his sons was very disturbed and lived there, but I’m afraid I don’t know anything more about it.”

She said Reade Elliott “would occasionally bring the most lovely ripe tomatoes” to Georgetown from his Purcellville home, “and Le Roi, of course, would bring them to me, which was the nicest thing.”

Because she doesn’t drive, Wilson said, Le Roi Elliott would take her with him when he went grocery shopping at a Safeway. Rather than discuss their personal lives, she said, “we would talk about events going on in the world.”

Wilson said that Le Roi Elliott was sweet-natured, as was his wife, and that he enjoyed listening to opera in his home on Sundays.