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

The mentally ill man suspected of fatally stabbing his 88-year-old father in their Georgetown home Sunday morning suffered a heart attack and died while being treated at a hospital, D.C. police said Tuesday.

Bradford Nelson Elliott, 56, died Monday before he was formally charged in the case, said Saray Leon, a police spokeswoman. Elliott had been arrested but had not appeared in D.C. Superior Court, Leon said. No other details were provided.

Elliott was accused of cutting his father, Le Roi Elliott, and his mother, 81-year-old Vaughn Elliott, whose injuries were not considered life-threatening. Police said Elliott lived with his parents in the house in the 3300 block of Q Street NW and had been involved in a scuffle with them.

D.C. police said the attacks on Bradford Elliott’s parents appear related to mental illness, and a former neighbor and court records provided information about problems involving Elliott and some of his neighbors dating back to at least 2007. The former neighbor said he tried repeatedly to get help for Elliott.

Relatives of the Elliotts did not return phones calls Tuesday. Le Roi Elliott’s daughter said over the weekend that her father was a retired international public relations manager for Texaco. She said her father was originally from Michigan but had lived in the D.C. area since 1985.

The violence erupted Sunday morning inside the $1 million house where Bradford Elliott lived with his parents. Police said that Elliott’s mother called 911 after being cut about 6:30 a.m. and that officers who arrived were greeted by Bradford Elliott, whose hands were covered with blood. They immediately arrested him and took him to a hospital.

Le Roi Elliott was found unconscious in an upstairs bedroom and was taken to a hospital, where he died of his injuries. His wife, also hospitalized, is expected to recover, authorities said. Police said that the couple’s other son, Reade Elliott, spoke with homicide detectives at the family home and told them that his brother had a long history of mental illness.

On Jan. 6, 2007, D.C. police arrested Bradford Elliott outside the family home. A woman told police that Elliott had assaulted her two blocks away on Wisconsin Avenue, slapping her in the face and pushing her and another woman into the street. Court documents say he then entered a house and broke two lamps valued at $800.

Witnesses held him until police arrived, according to a court document filed in the case. He was charged with assault and destruction of property and taken to a psychiatric hospital for observation, the document says. He pleaded guilty to both charges, was given a 180-day suspended jail sentence and was placed on electronic monitoring.

A few years later, in 2010, another neighbor, who asked to remain unnamed in this article, filed complaints urging city officials to take action against Elliott, whom he viewed as a danger to the community. The man, who has since moved, alleged that Elliott had thrown trash on his yard and put items in his mail slot, including a fake check for $85 million. The neighbor said Elliott’s parents were incapable of dealing with him.

“This person needs to be placed in a home where someone can care for him,” the man wrote to then-Mayor Adrian M. Fenty (D), according to a copy of an e-mail he provided to The Washington Post. He wrote that a commitment “needs to happen before he has an encounter with my daughter.”

A D.C. official wrote to the neighbor that the city had advised Elliott’s mother on how to handle the problem but that “she is not interested in filing a police report.”

Paul Duggan contributed to this report.

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