Story highlights Tonya Thomas called three of her wounded children home and shot them again, killing them

In all, Thomas killed her four children before shooting herself, police say

Children's father doesn't live with the family; police say he's distraught

Authorities received calls about past incidents at the home, including a "domestic incident"

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, police said.

The three children went to the neighbor's house to say their mother had shot them, Brevard County Sheriff's Office Lt. Tod Goodyear said, according to CNN affiliate WKMG.

The mother, Tonya Thomas, 33, then called them back home, Brevard County Sheriff's Office Lt. Tod Goodyear told reporters.

The mother then shot them again, killing them, Goodyear said, according to WKMG.

"I'm a father and I've got kids. I cannot comprehend a person doing that to their child -- calling them back to the slaughter," Goodyear said, according to WKMG.

Responding deputies arrived at the house and heard shots.

They discovered Thomas' 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 a 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 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 the gun but they believe Thomas was the killer.

"Everything points to it being her."