A man was found dead Saturday morning inside a South Philadelphia rowhome that had been set ablaze in an arson, according to police.

A 90-year-old woman who lived in a neighboring home on the 200 block of Tree Street was also injured as she tried to evacuate, police said.

Authorities said they responded to reports of a house fire on the block around 5:29 a.m. When first responders entered the home, police said, they found a man’s body inside. Authorities did not release the victim’s name or age.

The injured neighbor, whom police also did not identify, was taken by medics to Jefferson Hospital in stable condition, police said. They did not provide details about her injuries.

The fire marshal determined that the incident was an arson, police said, and homicide detectives were notified.

The blaze was one of three house fires in three hours that the Fire Department said it responded to Saturday morning.