Johnathan Walker:A teen killed his father in 2023. Now, he is charged with his mom's murder.

In what officials called a "cold-blooded murder,Johnathan Walker" a Florida teen was charged with murder in his mother's fatal stabbing less than two years after he was arrested, but never charged, for fatally shooting his father in Oklahoma.

Polk County Sheriff's Office deputies responded to a 911 call about 6 p.m. Sunday at a mobile home in The Hamptons, a senior community in Auburndale, Polk County Sheriff Grady Judd said during a Wednesday press conference.

The city is in central Florida about halfway between Orlando and Tampa.

The teen told 911 dispatchers his mother "fell on a knife," after they got into a fight, Judd told reporters.

The caller claimed his mother, Catherine Griffith, 39, lunged at him with a knife and fell on it, suffering a stab wound to her neck, Judd said.

5 shot in southeast Virginia:2 dead, 3 injured in Suffolk shooting near bus service station

Teen charged with killing mom immediately asks to speak with a lawyer

When deputies arrived and met the teen outside the mobile home, he immediately asked to speak with a lawyer, Judd said, saying he knew his legal rights.

"It's a cold-blooded murder," Judd said.

Inside the home, deputies found Griffith had been stabbed in the neck with a 12-inch kitchen knife. The woman was pronounced dead at the scene.

The mobile home belongs to the teen's grandmother, who authorities said was at a secondary home in the Keys at the time of the killing.

A preliminary investigation found the home's interior was neat and clean, with no evidence of a physical fight.

During Griffin's autopsy on Monday, the medical examiner determined she died from a deep knife wound to the neck inconsistent with an accidental injury.

"The medical examiner said it is not reasonable or plausible that she died the way that [the teen] said she did," Judd said.

'Let me go!'

Witnesses told police they watched the pair argue outside the home earlier in the day before the boy grabbed his mother by the hair and dragged her inside.

"Let me go!" Judd said Griffith pleaded at the time.

During an interview with police, the grandmother told detectives about past instances in which the teen physically or verbally threatened his mother, Judd said, including multiple threats to kill her.

Last September, the teen was hospitalized in nearby Charlotte County where he lives, under the state's Baker Act, which allows anyone deemed to be a threat to themselves or others to be detained for 72 hours for psychiatric evaluation.

Upon his release, Judd reported, the teen said, "I'll kill myself or I'll kill my mother by shooting or stabbing her." The teen was readmitted under the Baker Act and held for an additional three days.

Three months later, the teen was arrested for domestic violence against his mother after, Judd said, his mother disciplined him by taking away his video game privileges, and he pushed her to the ground and stomped on her.

Then in February, the teen had an argument with his mother and fled from Charlotte County to his grandmother's home in Auburndale. Polk deputies got involved as the grandmother said the family didn't feel safe, and because the teen was reported as a missing person, turned the boy over to the state's Department of Children and Families.

'My son is not a monster':Mother of Georgia shooting suspect apologizes in letter

Teen charged with murder in mother's death was arrested in Oklahoma for killing dad

In February 2023, police in Oklahoma arrested the teen in connection to his father's killing after he claimed his dad pulled a knife on him so he shot him in the head and chest.

He was charged with first-degree murder, but the charge was dropped shortly after because authorities said they could not disprove the teen's self-defense assertion.

Sheriff's office has asked district attorney to prosecute teen as adult

The teen remained in custody at the Polk County jail Friday. He was charged with first-degree murder, among other charge including kidnapping, Judd said.

The sheriff's office, Judd said, has asked The State Attorney's Office 10th Judicial Circuit, which includes Polk County, to prosecute the teen as an adult.

As of Friday, the office's top prosecutor Brian Haas had not announced his decision.

If evidence is found or developed during the Polk County investigation, Judd said authorities in Oklahoma will reopen the closed murder investigation.

Natalie Neysa Alund is a senior reporter for USA TODAY. Reach her at [email protected] and follow her on X @nataliealund.