The creepy still shows three individuals, each dressed in dark hoodies and full face masks.
Investigators say the trio intentionally started the blaze that killed five family members, before fleeing the scene in a dark four-door sedan.
Denver PD are offering a $14k reward for information leading to arrests.
Djibril Diol and his wife Adja, their 3-year-old daughter Kadidia, Djibril's sister Hassan Diol, and her infant daughter Hawa Beye, all lost their lives in the arson attack.
PLZ RT: Five people were killed in fire in the 5300 block of N Truckee Street. The fire appeared to be deliberately set by unknown persons who fled the area. Anyone w/info on this homicide is asked to call @CrimeStoppersCO at 720-913-7867 and you could earn a $14k reward! #Denverpic.twitter.com/7xbU2XQWDH
"We have indication through some evidence that it was an arson," he said, but refused to elaborate any further for fear of derailing the investigation.
He said that there was no indication of any prior trouble at the address.
Friends of the family in the tight knit community said Diol was an engineer, while both his wife and sister worked for Amazon.
"What would our community do to be a target?" one friend asked the publication.
A GoFundMe to raise money to repatriate the remains has already raised over $60k.
"This is a devastating time for Denver, for this community, and our hearts and our prayers go out to this community," Pixley added. "We really want people to understand that we do feel for them right now."