Mysterious voicemail latest clue in Washington D.C. mansion fire

WASHINGTON (WPVI) -- More details are emerging in a murder mystery in Washington D.C.

Police have a new clue about a wealthy family, and their housekeeper who were found dead inside a burning mansion last week.

Washington D.C. police are desperately searching for clues in the deadly fire which happened near Vice President Joe Biden's home.

Wealthy businessman Savvas Savapolous, his wife Amy and what authorities believe are their 10-year-old son and their housekeeper Vera Figueroa were found dead when firefighters arrived on the scene.

New video shows who police are calling a person of interest - taken miles away from the family's home, but close to where the Savapolous' blue Porsche was found set on fire.

Longtime family housekeeper, Nelitza Gutierrez is now shedding light on the mysterious quadruple homicide.

She told ABC News that she was with Savapolous the day before the fire and he said his wife was going out that night.

This new detail seems to contradict a message left by Savapolous for a longtime employee that night that said: "I hope you get this message, um, Amy is in bed sick tonight and she was sick this afternoon."

According to Gutierrez, Vera Figueroa's husband came to the Savapolous home looking for his wife, banging on the front door and allegedly hearing shuffling noises coming from inside.

Moments later, she claims Figueroa's husband received a call from Savapolous telling him his wife was staying the night.

"I wouldn't be surprised if somebody wasn't already in the house because obviously the bad guys would not want anybody else in the house," said former FBI agent, Brad Garrett.

There is a $25,000 reward for anyone with information that meads to an arrest and conviction.

As police continue to search for suspects, the Savapolous' two surviving daughters are now living with their grandparents.