DENVER (AP) — Police on Wednesday announced a $40,000 reward for information leading to the arrests of those responsible for setting a house fire in Denver that killed five recent immigrants from the West African nation of Senegal.

Lt. Matt Clark with the Denver Police Department’s Major Crimes Division said during a news conference that investigators have fielded about four dozen tips following the Aug. 5 fire and have reviewed “countless hours” of video footage from various surveillance cameras in the area.

Police also have released a surveillance photo showing three suspects wearing full face masks and hoodies. Investigators say the three fled in a dark-colored sedan after the fire was set in the Green Valley Ranch neighborhood, a relatively new development of closely spaced homes near Denver International Airport.

Killed were Djibril and Adja Diol, along with their 22-month-old daughter Khadija, as well as relative Hassan Diol and her infant daughter Hawa Baye. Three other people managed to escape by jumping from the second floor of the home.

“It makes it even harder when we had kids, babies that were caught in the middle of this tragedy. We owe it to them. We owe it to them to solve this crime,” said family spokesman Papa Dia, who wore a T-shirt printed with the photos of the five victims.

Police, fire officials and the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives are investigating because there are indications that it was arson. Authorities have not elaborated on the evidence because they say they do not want to compromise the investigation.