Police investigating three other violent deaths in District since Friday.
Police said in court papers that all four victims were stabbed and were held more than 19 hours.
Daron Dylon Wint, charged in the gruesome killings of a NW Washington family and their housekeeper, was apprehended Thursday night in D.C., Police Chief Cathy L. Lanier confirmed.
The expected grand jury action leaves the most significant charges in the case unchanged.
Authorities believe Daron Dylon Wint, of Maryland, held four people captive inside the multimillion-dollar Northwest home before it was set on fire.
Chief declines to comment on possible motive behind deaths of Savopoulos family, housekeeper
The city has a long history of bloodshed. And it’s only gotten worse since the recent upheaval.
Before the four were found dead in a burning home, a housekeeper received puzzling messages.
Lt. Kevin McRae was the District’s 100th firefighter to die in the line of duty; his cousin was the 99th.