A shooting inside a rural southern New Jersey home left two children dead and two family members critically injured, police told Reuters on Thursday.

Multiple family members were present inside the Tabernacle, New Jersey, home when an unidentified suspect open fired sometime Wednesday night, killing a boy and girl and wounding another boy and woman.

But it wasn't until around 9 a.m. the next morning when a relative called police to the single-family home, State Police Captain Stephen Jones told Reuters. The uninjured relatives did not hear the gunshots, Jones said.

After police arrived the boy and woman were transported by helicopter to Camden's Cooper University Hospital, where they are in critical condition, a hospital spokeswoman told the news agency.

The names and ages of the victims have not been released. Police also did not say if they have a suspect, but they suggested they have an idea who the assailant could be.

"There's not a massive manhunt going on," Jones said.

Sources told WABC that a mother who lives in the Holly Park Drive home allegedly committed the killings in an attempted murder-suicide.

Local residents also said there were two related families living in the house, located in New Jersey's rural Pinelands, and that it was inherited from the children's grandparents.

Police were still on the scene as of Thursday afternoon in the quiet town of Tabernacle, which has a population of 7,000.

"It's an active scene," State Trooper Alina Spies told Reuters. "We have a lot of troopers out there investigating, trying to process everything."