Christal Hayes | USA TODAY

USA TODAY

Hillsborough County Sheriff's Office

A woman has been charged with murder after police say she tossed her 4-year-old daughter into a Florida river.

The event happened Thursday afternoon to the horror of witnesses who watched the woman wading in the waters of the Hillsborough River and called authorities.

Tampa police say the woman, Shakayla Denson, 26, was arrested on several charges, including first-degree felony murder in the death of her daughter, Je'Hyrah Daniels.

"It's a completely tragic event," Tampa Police Chief Brian Dugan told reporters at the scene, adding investigators were still trying to make sense of what happened and why. "We’re still piecing the whole thing together."

Denson, authorities say, first stole a car from a local auto shop and then drove to the water with her daughter.

After parking, "witnesses say she waded into the Hillsborough River with her child," Tampa police said in a news release.

#BREAKING | Mother Who Tossed Child in River Charged with Murder pic.twitter.com/PkkBaVZfu1 — TampaPD (@TampaPD) August 3, 2018

She made it about halfway across the water, then "tossed" the child and retreated to the street, the release said.

Police got multiple calls about the incident and were able to quickly find Denson, who was walking nearby.

Romano Muniz, 31, who lives nearby, told The Tampa Bay Times he watched some of the rescue efforts. He said he saw crews pull the girl's "lifeless" body from the river.

"It’s disgusting," Muniz said.