D.C. police have released video images of a person of interest in the deaths of four people in a house in an upscale neighborhood in Northwest Washington. (YouTube/DC Metropolitan Police Department)

D.C. police said Saturday night that they are seeking a person of interest in the deaths of four people in a house in an upscale neighborhood in Northwest Washington.

Police said the individual may have been operating a Porsche automobile linked to the house.

They also provided video footage that appeared to show a man wearing a hoodie moving rapidly behind a building.

The announcement came in the deaths of Savvas and Amy Savopoulos and two others, believed to be their son and one of their housekeepers.

The Savopoulos family had been having a busy week. The husband was trying to get a new martial arts center in Chantilly, Va., ready for a grand opening, and he enlisted the help of one of his housekeepers. His wife was ill, and their 10-year-old son was recovering from injuries suffered in a go-kart crash.

Savvas Savopoulos and Amy Savopoulos at the Starlight Children’s Foundation MidAtlantic’s Wine Dinner in 2008. (Tony Powell/Washington Life Magazine)

Before the late night police announcement, the days and hours leading up to the deaths of the husband and wife and the two others had come into sharper focus Saturday with new details from police records. They show attempts by friends and relatives to reach the victims Thursday morning, before they were found dead that afternoon in a burning home in Northwest Washington.

These records show a series of text messages and voice mails from both Savopouloses to the housekeeper who had been helping in Chantilly, telling her not to come clean at their D.C. home Thursday, as was her normal routine. Savvas Savopoulos also let her know in a Wednesday night voicemail that the housekeeper who was later found dead had planned to stay overnight at the family’s home and asked that she inform the woman’s family because her cellphone battery had died.

Nelitza Gutierrez, the housekeeper who received the messages and has worked for the family for 20 years, said in an interview Saturday that the series of messages left her with the impression that something was amiss with her employers. She said Savvas Savopoulos told her in person Wednesday that his wife had plans to go out, but said in the voice mail left that night that Amy Savopoulos had been sick in bed all day.

“It was something very suspicious because I felt his voice was really tense,” Gutierrez said in Spanish. “And it was different than what he had said to me before.”

She said she first listened to the message Thursday morning and immediately called Amy Savopoulos “to see if she was okay, but she never answered.”

The police documents also show what appears to be an unusual amount of activity last week around the victims’ Woodland Drive NW home. Neighbors reported seeing a man banging on the door of one home, an aggressive vacuum cleaner salesman at another house, reports of a prowler, and what a witness said could have been the Savopouloses’ blue Porsche speeding down the street the day before the deaths were discovered.

Police have been sorting through a great deal of potential evidence in an effort to learn what happened to Savvas Savopoulos, 46, his wife, Amy, 47, and the two others, tentatively identified as the couple’s 10-year-old son, Philip, and a 57-year-old housekeeper, Veralicia Figueroa, of Silver Spring, Md.

Police have said all four deaths are being investigated as homicide. They said Friday that three victims had wounds. They said the family’s Porsche 911, which was missing for several hours Thursday, was found burned in a church parking lot in Hyattsville, and that the fire at the home was intentionally set.

The deaths have shocked this enclave of Upper Northwest Washington and the District’s society circles. The couple were active donors to both social and political causes, and attended St. Sophia Greek Orthodox ­Cathedral. Savvas Savopoulos was president and chief executive of American Iron Works, a leading custom steel and iron manufacturing company that helped build Verizon Center and CityCenterDC.

Relatives of the Savopouloses have spoken briefly about the family and the incident, but they have been too overwrought for more in-depth interviews. The couple have two surviving daughters — Abigail Savopoulos is a senior at Mercersburg Academy, an elite private school in Pennsylvania, and is scheduled to graduate this week, and Katerina is a junior at Peddie School near Princeton, N.J. Their youngest child, Philip, was a student at St. Albans School in the District.

Gutierrez, who was close with Figueroa, said her friend had planned to soon return to her native El Salvador. She said Figueroa was at her wedding, and that she was there for her baby shower and, later, her daughter’s first communion.

D.C. Police Chief Cathy L. Lanier said Friday that police were still working on a timeline, and looking for a motive. It remains unclear whether anything was taken from the two-story red brick house. Lanier said detectives were working to track the Porsche, and asked anyone who saw it Wednesday or Thursday to contact police.

Police records also show Savvas Savopoulos working hard last week getting the Chantilly project ready for a Friday opening. The Chantilly property was closed Saturday but a business owner who works nearby said he has seen recent activity there.

Gutierrez said in the interview that Savvas Savopoulos had asked her to help at the studio on Tuesday, Wednesday and Friday, instead of at the couple’s home on Thursday.

On Wednesday night, Gutierrez told police, she got the voice mail from Savvas Savopoulos saying that his wife was sick and Philip was home from school with an injury. He told her that Figueroa was going to stay the night to help, but that her phone had died and she had no charger. He asked the housekeeper to call Figueroa’s relatives to relay the message.

In an interview, she said she had never known Figueroa to stay overnight at the home and thought it was odd. “Never, never did she stay over.”

Also Thursday morning, one of Savopoulos’s assistants apparently left a package outside the Woodland Drive house, according to the police records. That person then drove to Chantilly and was there through the day. And at roughly the same time, Figueroa’s husband went to the house to check on his wife. There apparently was no answer.

Minutes before 10 a.m., Gutierrez got a text message from Amy Savopoulos: “I am making sure you do not come today.” Gutierrez, who was then cleaning another home in McLean, replied that she would not be coming, per Savvas Savopoulos’s earlier orders, according to the police documents.

Victoria St. Martin contributed to this report