INDIANAPOLIS – A father and son have both been sentenced to more than 3 years in federal prison for setting off an explosive under an overpass near the Indianapolis Motor Speedway in 2019.

Wayne Turner pleaded guilty to possession of an unregistered destructive device and was sentenced to 46 months in prison. His son, Isak Turner, pleaded guilty to the same charge and was sentenced in February to 42 months in prison.

Both will be supervised by the U.S. Probation Office for three years upon their release.

The charges stemmed from a December 2019 incident in which the two men lit an improvised explosive device and threw it under the bridge on 16th Street.

The incident happened just after 9 p.m. Police were called to the 3600 block of East 16th Street, west of Tibbs Avenue and east of the Indianapolis Motor Speedway. Investigators found a post-blast crater in the dirt under the 16th Street bridge.

Wayne Turner (left) and Isak Turner (right)

Wayne Turner had assembled the device using materials he kept at his apartment, according to court documents. They parked their car by the railroad tracks near the 1200 block of Olin Avenue and then walked to the railroad bridge over 16th Street.

Isak Turner ignited the explosive and threw it from the bridge. The railroad bridge and a light fixture were damaged. Debris also hit a passing vehicle, although the driver was not hurt.

Speedway police found the Turners and a third individual who was not charged walking on the bridge. Police eventually executed a search warrant at Wayne Turner’s apartment off East Washington Street, where they found materials used to make explosives. Both Wayne and Isak were subsequently arrested.

A witness told police they’d been out celebrating Wayne Turner’s birthday that night.

According to federal prosecutors, the device thrown from the bridge was a destructive device as defined by the National Firearms Act. It was not registered to either of the men, as required by law.

Wayne Turner had been arrested in a similar case before. In May 2016, the night before that year’s Indianapolis 500, he detonated an “M-80” style device and tossed it over a fence onto IMS property.

The resulting explosion sent people scrambling. He then set off a second device next to a barricade on Georgetown Road, intensifying the panic. Police found him, apparently intoxicated, in possession of at least eight cylindrical explosive devices with ignitable wicks. He was convicted of criminal recklessness in that case.

The investigation into the December 2019 explosion involved the Bureau of Alcohol, Tobacco and Firearms (ATF), Indianapolis Metropolitan Police Department and Speedway Police Department.