The bodies were found at the Robert Morris Apartments on West Bridge Street.

MORRISVILLE —A woman and her daughter are being charged in the death of five relatives, including three children, who authorities said were killed in borough apartment Monday.

The 45-year-old woman and her 19-year-old daughter were expected to be arraigned overnight, said Bucks County District Attorney Matthew Weintraub. The mother, Shana S. Decree, and Dominique Decree each will be charged with five counts of homicide and one count each of conspiracy.

Weintraub said the dead included the older woman's 13-year-old son Damon Decree Jr. and her 25-year-old daughter Naa'Irah Smith Authorities said the women also killed Shana Decree's 42-year-old sister Jamilla Campbell, of Trenton and Campbell's twin 9-year-old daughters Imani and Erika Allen.

“This is a tragedy,” Weintraub said, adding that the family of the victims are heartbroken. “The people that committed these atrocious acts are in custody and we’ll make them pay for their crimes.”

Police said they initially found three females and one male in a bedroom in a first floor, two-bedroom unit at the Robert Morris Apartments on West Bridge Street. The two defendants were taken to Jefferson Bucks Hospital in Falls, authorities said. One was having seizures and another was conscious when police found them.

Police discovered the bodies while doing a welfare check shortly after 4 p.m., and spent the night investigating. Neighbors said three people lived in the apartment, but that other family members frequently visited.

The fifth body, believed to be one of the children, was found Monday night in the unit hours after the investigation began. Police confirmed the discovery around 10 p.m. Monday.

The county coroner arrived at the apartment complex Monday night.

Morrisville police Chief George McClay said there was initial concern the incident was the result of hazardous materials inside the apartment but that was ruled out quickly after a check by firefighters and the county's hazmat team.

McClay confirmed late Monday night there was no danger to the public.

Borough police and county detectives are still investigating. Authorities did not release a motive Monday night.