Jacksonville Serial Robber Convicted by Jury for Firearms Possession

Jacksonville, Florida - A federal jury has found John Flowers Grissom (55, Jacksonville) guilty of possession of ammunition by a convicted felon and possession of an unregistered, short-barreled rifle without a serial number. Grissom faces a minimum of 15 years, and up to life, in federal prison. His sentencing hearing is scheduled for September 30, 2026. U.S. Attorney Gregory W. Kehoe made the announcement.

Grissom was initially charged by criminal complaint on November 20, 2024.

According to evidence presented at trial, on September 30, 2024, three young men were playing basketball in Jacksonville when one of them discovered he had lost his keys. While retracing his steps, the young man encountered Grissom and asked whether Grissom had seen his keys. Later, as the young man circled the block in a vehicle, they observed Grissom hiding outside of his residence with a short-barreled rifle equipped with a red laser. As the young men drove by Grissom's residence, Grissom pointed the short-barreled rifle at the young men.

Fearing for their lives, the young men called the Jacksonville Sheriff's Office (JSO) and provided officers with detailed physical descriptions of Grissom, his residence, and his firearm. JSO officers responded to the residence in an attempt to make contact with Grissom. Upon arriving at the residence, the officers observed Grissom's window lit up from inside and observed his door quickly open and shut. The officers proceeded to bang on his door and window and announced their presence outside. For more than two hours, Grissom pretended not to be home.

Ultimately, Grissom exited the home and was arrested. When interviewed, Grissom stated that he was on heavy medication and did "it" because he was scared due to recent robberies in his neighborhood. A lawful search of his residence was conducted, and officers located rifle ammunition in Grissom's toilet, an upper receiver for an AR15-style rifle underneath the covers of his bed, and the lower receiver and stock for the rifle inside a hole in his box spring. A bolt carrier and ammunition magazine were found in the trash. The barrel of the rifle measured approximately 8.5 inches, subjecting it to regulation under the National Firearms Act (NFA). A search of the National Firearms Registration and Transfer Record revealed that the firearm was not registered to Grissom. The firearm had been privately made and did not bear a serial number as required under the NFA. As an eleven-time convicted felon, Grissom is prohibited from possessing firearms and ammunition under federal law.

The jury further found that Grissom had three or more convictions for robberies that were committed on different occasions, thus subjecting him to an enhanced penalty as an Armed Career Criminal.

This case was investigated by the Bureau of Alcohol, Tobacco, Firearms and Explosives and the Jacksonville Sheriff's Office. It is being prosecuted by Assistant United States Attorneys Laura Cofer Taylor and Rick Lasseter.