Teen arrested in mother's stabbing death, 19 months after fatally shooting father

A Florida teenager has been charged with murder in the fatal stabbing of his mother, less than two years after he was arrested for fatally shooting his father but never charged, authorities said.

Polk County Sheriff Grady Judd said during a Wednesday press briefing that the teen had previously allegedly threatened to kill his mother before Sunday's "cold-blooded murder."

The stabbing occurred after the teen, 17-year-old Collin Griffith, and his mother, 39-year-old Catherine Griffith, were seen having an altercation outside a mobile home in Auburndale, according to Judd.

"There were witnesses outside the mobile home that actually saw Collin drag his mother into the house by the hair on her head," the sheriff said.

Griffith called 911 Sunday evening to report that his mother "fell on a knife" and was bleeding from the neck, Judd said. The teen reportedly said his mother had lunged at him with the knife when she fell on it during a prolonged fight inside the home, according to Judd.

The home belongs to the teen's grandmother, who was not there at the time of the incident, Judd said.

When deputies arrived, the teen met them outside and was "calm, cool, collected – not upset," Judd said. Griffith reportedly told them, "I know my rights, I want an attorney," according to Judd.

A bloody kitchen knife with an 8-inch blade was found inside the home, the sheriff said.

During an autopsy conducted on Monday, the medical examiner determined that Catherine Griffith died from a deep knife wound to the neck that was inconsistent with an accidental injury, according to Judd.

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

Collin Griffith is in custody and has been charged with first-degree murder, Judd said, adding that they have asked the state attorney's office to prosecute the teen as an adult.

The State Attorney's Office 10th Judicial Circuit, which includes Polk County, told ABC News on Thursday they have no comment on the case at this time.

It is unknown if Griffith has an attorney. ABC News' attempts to reach his grandmother were unsuccessful.

Judd said as investigators started to "peel back the layer of this onion," the teen's family told investigators that he had previously been physically or verbally confrontational with his mother.

Sheriff's office reports out of Charlotte County in Florida, where Collin Griffith and his mother lived, showed that he had allegedly threatened to kill her in statements purportedly made in September 2023 and, most recently, in February, according to the charging affidavit for his mother's murder.

Collin Griffith was also arrested by the Charlotte County Sheriff’s Office for domestic violence battery against his mother in November 2023, according to Judd.

"She was disciplining him and took his video game privileges away, so he beat up his mother," Judd said. "He pushed her to the ground and he stomped on her."

Days before the stabbing, Collin Griffith and his mother had an argument about chores and he went to his grandmother's home, Judd said. Catherine Griffith went to the grandmother's home on Sunday to bring him back to hers, and she and her son were seen arguing outside of the grandmother's home around 4:30 p.m., fewer than two hours before the teen called 911 to report the stabbing incident, Judd said.

While investigating the stabbing, the sheriff's office learned that authorities in Oklahoma also had arrested the teen last year in connection with the fatal shooting of his father, Charles Griffith, at their home in Lincoln County.

Collin Griffith told authorities that he shot his father in self-defense on Feb. 14, 2023, during an argument that turned physical, according to Adam Panter, the district attorney for Oklahoma's 23rd District, which includes Lincoln County.

During a 911 call, the teen said he grabbed a rifle and shot his father twice after his father chased him into a bedroom while armed with a knife, according to the district attorney.

"At the start of his police interview, he requested an attorney and the interview was terminated, so the only version of events that we were able to obtain was what Collin said on the 911 call, which was consistent with the evidence we found at the scene," Panter said in a statement to ABC News.

State police investigated forensic and digital evidence and no charges were ever filed against the teen in the case, Panter said.

"Ultimately, after evaluating all of the evidence and possible theories, it was determined that we could not rule out self-defense and as a result, declined to file any formal charges," Panter said.

Both Panter and Judd said any relevant information obtained in the investigation into the mother's death will be considered in connection with the shooting of the teen's father.

"If any new evidence is obtained that is both relevant and credible to our investigation into the death of Collin Griffith’s father, we will certainly re-evaluate the case and make a new determination if necessary," Panter told ABC News.

Following the Oklahoma shooting of his father, Collin Griffith came to Charlotte County in Florida in March 2023 to live with his mother, Judd said.

He was "being intensely watched" by the county's sheriff's office prior to the stabbing, Judd said. Griffith had been placed on active juvenile probation following his arrest in November 2023 for battery domestic violence in connection to his physical attack on his mother, according to an affidavit.

A spokesperson for the Charlotte County Sheriff's Office told ABC News that its juvenile unit had been working with the teen and his family "in various ways to include connecting them with available resources."

"I cannot expand any further on that as I am not privy to those interactions, and because he is a minor," the spokesperson said.

The Florida Department of Children and Families (DCF) had also been in contact with the family, including after the teen ran away from home in February following an argument with his mother, according to Judd.

A spokesperson for DCF, which investigates allegations of abuse, neglect or abandonment, said information regarding its investigations is confidential, per state law.

Judd said they are looking into Collin Griffith's history and interactions with other agencies in Florida and Oklahoma as they investigate the case.

"My question is, was there anything else that could have been done?" he said

He noted that the Charlotte County Sheriff's Office did a "remarkable job keeping up" with Collin Griffith.

In addition to murder, Collin Griffith has been charged with kidnapping and violation of a no-contact order, the sheriff's office said. The charges stem from his juvenile probation in Charlotte County for battery domestic violence, with conditions including that he have no contact with his mother, according to the affidavit.