JACKSONVILLE, Fla. — A Jacksonville man described by federal prosecutors as a serial robber is facing at least 15 years in prison after a jury convicted him of firearms offenses.
The U.S. Attorney’s Office for the Middle District of Florida said John Flowers Grissom, 55, was found 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 Sept. 30.
According to evidence presented at trial, three young men were playing basketball in Jacksonville on Sept. 30, 2024, when one of them realized he had lost his keys.
Federal prosecutors said the man retraced his steps and asked Grissom if he had seen the keys.
Later, as the group circled the block in a vehicle, they saw Grissom outside his home with a short-barreled rifle equipped with a red laser, prosecutors said.
As the men drove by, prosecutors said Grissom pointed the rifle at them.
The men called the Jacksonville Sheriff’s Office and gave officers a description of Grissom, his home and the firearm.
Prosecutors said officers went to Grissom’s home and saw a window lit from inside and the door quickly open and shut. Officers knocked on the door and window and announced themselves, but prosecutors said Grissom pretended not to be home for more than two hours.
Grissom eventually came outside and was arrested.
According to prosecutors, officers later searched the home and found rifle ammunition in a toilet, an upper receiver for an AR-15-style rifle under bed covers, and the lower receiver and stock inside a hole in a box spring. A bolt carrier and ammunition magazine were found in the trash.
Federal prosecutors said the rifle had an 8.5-inch barrel, was not registered to Grissom and did not have a serial number.
The jury also found that Grissom had three or more robbery convictions committed on different occasions, subjecting him to an enhanced penalty as an armed career criminal.
The case was investigated by the Bureau of Alcohol, Tobacco, Firearms and Explosives and the Jacksonville Sheriff’s Office.
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