Police in Florida arrest a 19-year-old after they say they found written shooting spree threats during a routine traffic stop

Authorities in South Florida say they arrested a 19-year-old this week after they say they found written threats for a shooting spree and other attacks in his vehicle during a routine traffic stop.

A Jupiter, Florida, police officer pulled over Henry Horton IV on September 18 for a headlight that was out on the white pickup truck he was driving, according to a probable cause affidavit from the Palm Beach County Sheriff's Office.

During a search of Horton's vehicle, the officer found multiple handwritten notes with a plan to purchase firearms and "kill everyone at OHS (Okeechobee High School) with my guns," the probable cause affidavit says.

Horton graduated from the high school, located in Okeechobee County, in May 2022.

Horton told the officer he had previous mental health issues and had "been having multiple thoughts about mass homicide and want(ing) to execute them once he turned 22 years old," according to the affidavit.

He had plans to kill 15 people from the high school on January 2, 2026, his 22nd birthday, according to the affidavit.

Horton said while living in Virginia, he voluntarily admitted himself to a medical facility for a mental health evaluation due to having similar thoughts, the affidavit stated.