VAN BUREN COUNTY, Ind. -- A 41-year-old Bloomingdale, Michigan man is dead after ingesting an "unknown substance" during a traffic stop Wednesday morning.

The Van Buren County Sheriff's Office reports members of the Narcotics Unit and Uniform Response Division witnessed a Ford pickup truck commit multiple traffic violations around 9:54 p.m.

Authorities say they also recognized the driver as a person believed to have a suspended driver's license. Deputies then conducted a traffic stop.

During the stop, authorities observed the man ingest an unknown substance before taking a drink from a beverage.

As deputies got closer to the truck, they say the man ingested a second amount of the unknown substance.

The driver, identified as Nathan Matthews, was removed from the truck. Deputies observed suspected narcotics residue on Matthews' shirt and the vehicle's seat.

When asked multiple times, authorities say Matthews denied ingesting narcotics or possessing any illegal drugs. Deputies searched the vehicle, locating further evidence consistent with methamphetamine.

The report states deputies became concerned about Matthews' well-being based on their observations and evidence recovered.

Deputies then took Matthews to Bronson Lakeview Hospital for medical evaluation as a precaution.

While helping Matthews from the squad car to the emergency room, he became unresponsive.

Authorities say they immediately administered two cans of Narcan while hospital staff responded and began medical care.

Despite life-saving efforts, Matthews was later pronounced dead by Bronson Lakeview doctors.

Since this was an in-custody death, standard protocol was followed and the Michigan State Police were called to conduct an independent investigation.

MSP will investigate the circumstances surrounding the death, including interviews with witnesses and the involved deputies and detectives. The case will be forwarded to the Van Buren County Prosecutor's Office for review following the investigation's conclusion.

The investigation is ongoing.