Authorities identified the 22-year-old man who died in the Stillwater prison Saturday, and synthetic drugs may be involved.

A Tuesday news release from the Minnesota Department of Corrections said Dalmario Smith is the man officers found unresponsive in his cell about 3:30 a.m. Paramedics tried saving Smith but declared him dead about 20 minutes later.

It's unclear how Smith died, but officials do not believe foul play was involved. DOC investigators are looking into whether Smith ingested synthetic drugs after finding evidence in his cell.

"Minnesota, and prison systems across the nation, are experiencing challenges related to the introduction of synthetic controlled substances, frequently infused into paper that enters facilities through the mail," The Department of Corrections' news release said. "MCF-Stillwater recently began photocopying all incoming mail except for legal mail due to attorney-client privilege."

DOC Commissioner Paul Schnell vowed to pursue and prosecute those responsible if drugs caused Smith's death. As the Star Tribune reported, Minnesota is among many states battling a surge in "drug-soaked" mail being smuggled into prisons. One man earned two additional years for smuggling such contraband, but officials worry.

"Prison is a compressed environment, so it in many ways magnifies the effects that you would otherwise see on the outside," Melinda Williams, the assistant U.S. attorney in charge of leading the Minnesota office's criminal division, said in a previous interview. "I think one of our top priorities both in and outside prisons is overdoses."

Star Tribune staff writers Tim Harlow and Stephen Montemayor contributed to this article.