CALVERT COUNTY, MD (CBS/WUSA) -- Three people are dead and one 12-year-old was critically injured, in an apparent multiple murder-suicide and arson in Calvert County, Md., according to the Calvert County Sheriff's office.

All the victims are members of the same family. It happened at 1800 Candlelight Court in Owings, on Tuesday morning.

Investigators have identified the victims as 31-year-old Cynthia Hayward and her 2-year-old daughter Natalee. Investigators believe the pair were murdered by Cynthia Hayward's 32-year-old husband Frank, who committed suicide. The couple's 12-year-old son Frank Hayward III survived the incident and was airlifted to a hospital with burns and lacerations.

A fire had been set in the home and was burning when rescuers entered the house just after 9 a.m. Tuesday. The bodies of the mother and daughter were burned.

Investigators have not commented on how the victim's died. Handguns believed to be used in the incident were recovered from the home.

Sheriff's deputies went to the home in the Fairview subdivision of Owings this morning after an unidentified adult relative fled from the house and called 9-1-1 at about 8:30 a.m. to report a domestic incident, officials said.

A tactical team in an armored vehicle approached the house and entered, finding a fire burning inside and the victims on the first level of the large traditional-style home.