OAKLAND COUNTY, Michigan. – A man is behind bars in Oakland County for allegedly 3D printing guns and illegal gun accessories.

The suspect, whose identity has not been released, was arrested for carrying a concealed AR-15-style rifle while out on bail for a firearm crime.

During this investigation, authorities learned that the man was 3D printing, installing and selling firearm conversion devices. The Oakland County Sheriff’s Office said the devices turn a semi-automatic weapon into a fully automatic weapon.

Oakland County Sheriff Michael Bouchard said the converters are used in crimes such as drive-by shootings.

The sheriff also said that during a search, authorities recovered a 3D printer, a 3D printed gun and 13 conversion devices.

Formal charges are expected to be announced this week.