NORRISTOWN, Pa. (CBS) — Three people were killed, including a young child, and six others were injured after fire tore through a home in Norristown, Montgomery County.

Flames fire broke out around 4 a.m. Saturday inside a multi-unit rowhome in the 800 block Dekalb Street, near East Oak Street.

“There was heavy fire from the first floor,” said Norristown Fire Chief Tom O’Donnell. “Heavy smoke from the second and third floors.”

Neighbor Marco Vargas was one of several looking on as crews rescued those inside. He says his friend lives with two young daughters in one of the apartment units hit by the blaze.

“I saw the building on fire, smoke coming out of the windows and everything,” Varagas said. “(The girls) were looking really bad.”

Officials say two adults were found dead inside the home. A child was rushed to Einstein Medical Center, but later died. Five more adults were also hurt, along with a child who was taken to Children’s Hospital of Philadelphia in critical condition.

Investigators were working to piece together what sparked the blaze.

Pennsylvania State Police and Montgomery County detectives were handling the investigation. Chief O’Donnell says it’s unclear whether there were any working smoke alarms in the building, but he says when crews arrived, there were no alarms going off.

The blaze is the second fatal fire in Norristown this year.