One victim died Tuesday evening after a two-alarm fire broke out in two residential buildings near the Cow Palace in Visitacion Valley. According to witnesses, a large explosion was heard just before the blaze broke out.

The fire was reported around 5:30 p.m. in a wooden building near the intersection of Castillo Street and Geneva Avenue and spread to a neighboring building, Bay City News reports. San Francisco Firefighters had the fire under control by 6:09 p.m., but one victim was declared dead at the scene. The two critically injured victims were taken to a nearby hospital to be treated.

The cause of the evening fire is still under investigation and arson investigators were on the scene Tuesday evening. According to ABC7, the fire department received reports of an explosion just before the fire broke out. One witness claims to have seen a person being blown out of the home and one of the other victims may have jumped or been thrown from the building as well.

ABC7 has the video report: