(CNN) -- A Florida mother shot her four children early Tuesday morning before turning the gun on herself at her home in Port St. John, police said.
A neighbor heard shots at 4:50 a.m. and then responded to a knock at the door to find three of the children. The mother, Tanya Thomas, 33, called them back home, Brevard County Sheriff's Office Lt. Tod Goodyear told reporters.
Deputies arrived at the house several minutes later to hear more shots fired.
They discovered Thomas's eldest daughter, Pebbles Johnson, 17, wounded in the front yard. They drove a patrol car onto the lawn in an attempt to rescue her. Johnson was rushed to hospital but died from her wounds, Goodyear said.
The other children -- Joel Johnson, 12, Jazlin Johnson, 13, and Jaxs Johnson,15 -- were all dead, as was Thomas.
No suicide note was found in the home, but Goodyear said a witness told police he received a text from Thomas at about 3 a.m. that said she wanted to be cremated with the children.
"Unfortunately he did not see that text or read it on his phone until he woke up this morning ... well after the incident occurred," Goodyear said.
The children's father does not live with the family and Goodyear said he was distraught.
Goodyear said police do not have a motive.
He said authorities have received previous calls from Thomas' home pertaining to domestic violence.
Goodyear said he was having a hard time trying to understand how a mother could commit such a grisly act. He said she remained very calm when she called the children back to their house.
"I cannot comprehend as a parent doing this to their children ... calling them back in and shooting them," he said.
He said authorities have not yet determined the owner of then gun but they are pretty certain Thomas was the killer.
"Everything points to it being her."