Fla. Girl, 5, Was Thrown to Death off Bridge by Dad Whose Insanity Defense Was Rejected by Jury

A Florida dad who admitted to throwing his daughter off a bridge four years ago was found guilty of first-degree murder Tuesday.

A jury of nine men and seven women heard four weeks of testimony that John Jonchuck dropped his 5-year-old daughter, Phoebe, to her death.

Phoebe’s body was recovered from Tampa Bay on Jan. 8, 2015, about an hour after an off-duty police officer heading home said he saw Jonchuck’s white PT Cruiser stop on the Dick Misener Bridge in St. Petersburg.

After stopping on the bridge, Jonchuck “reached into the back seat and grabbed the girl,” police spokesman Mike Puetz told PEOPLE at the time. “Then he threw her over the railing and into the water.”

The officer says he heard a splash as the child fell into the bay below. He then radioed for help and climbed over the railing himself, hoping he could rescue the child. But “he couldn’t see her, because the current is extremely strong there,” said Puetz.

Both the prosecution and the defense acknowledged that Jonchuck, 29, killed his daughter, but the defense claimed that he was mentally ill at the time. They argued that he should be found not guilty by reason of insanity.

The jury ultimately decided that Jonchuck knew the difference between right and wrong. They determined he had planned the murder before reaching the top of the bridge. Prosecutors stated Jonchuck acted out of vengeance, killing the girl so her mother could never get full custody of her.

Court filings obtained by PEOPLE state that Jonchuck said he heard “voices” that told him to kill Phoebe. During interviews with a mental health doctor, Jonchuck said, “I was hearing voices saying that if me and Phoebe didn’t die, everybody was going to go to hell.”

RELATED: Florida Father Accused of Throwing 5-Year-Old Daughter Off Bridge

John Jonchuck | Pinellas County Jail/AP
John Jonchuck | Pinellas County Jail/AP

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Just hours before Phoebe’s death, police had questioned Jonchuck for acting erratically. His attorney at the time — with whom Jonchuck had been meeting in reference to his custody dispute — had called 911 after observing Jonchuck’s behavior.

The Department of Children and Families hotline also had received a call voicing concerns that Jonchuck was unstable. DCF placed a notation about the call in a file for a caseworker to handle at a later date. Twelve hours later, Phoebe was dead.

RELATED: John Jonchuck, Accused of Throwing Daughter off Bridge, Is Competent to Stand Trial: Judge

“I think both sides worked very hard to present their positions. And I am satisfied that justice was done,” Pinellas-Pasco State Attorney Bernie McCabe told the Tampa Bay Times. “My immediate reaction is killing children doesn’t make one a very sympathetic character.”

Officer Drew Vickers, who witnessed the murder, issued a statement praising the outcome.

“I am pleased with the verdict,” the statement reads, “and am glad to have some closure for Phoebe and her family after four long years.”

The verdict carries an automatic life sentence. Jonchuck was fingerprinted and taken into custody. He did not make a statement to the court.