On the same day a criminal investigation is launched into the deadly fertilizer plant explosion in West, a Texas paramedic who helped evacuate people has been arrested and charged with possessing a destructive device.

Authorities are not saying if the Texas Rangers and the McLennan County Sheriff’s investigation are related to the arrest of paramedic Bryce Reed.

Federal prosecutors say Reed did not enter a plea when he made his initial court appearance in federal court Friday in Waco. Assistant U.S. Attorney Mark Frazier would not release further details.

A fire erupted at the plant April 17 and a massive explosion rocked the town of West about 20 minutes later, killing 14 people.

Investigators have largely treated the incident as an industrial accident. But Texas law enforcement officials also launched a criminal investigation Friday.