A Bellevue man faces life in prison following two felony charges brought forward after a suspicious package arrived at the Bellevue Post Office that allegedly turned out to be heroin and cocaine.

Koby Slade Sliwicki, 29, has been charged with trafficking heroin and possession of cocaine following a joint investigation between the U.S. Postal Inspector’s Office and the Blaine County Sheriff’s Office, according to a news release from the Sheriff’s Office.

A probable-cause affidavit written by Blaine County Sheriff’s Office Detective Mike Abaid states that the Inspector’s Office contacted the Sheriff’s Office after a suspicious package headed for the post office in Bellevue was detected on Oct. 7.

Following a warrant to open the package at the Bellevue Post Office on Oct. 17, Abaid and a U.S. postal inspector discovered three magic markers with “several bindles containing small zip-lock baggies of a black tar substance … along with one containing a white powder substance,” the affidavit states.

Sliwicki was allowed to pick up the package on Oct. 18, and upon leaving the post office was placed under arrest, the report states.

According to the affidavit, Sliwicki “admitted he had been receiving these packages since around May and that he believed he had picked up six packages since that time.”

Sliwicki said the substances were black tar heroin and cocaine and all the packages were similar, with a comparable amount of heroin sent each time and cocaine in only some of the packages he received, the affidavit states.

Sliwicki faces a maximum of life in prison for the trafficking charge and a maximum of seven years in prison for the possession charge. He is scheduled for a preliminary hearing on Oct. 29, at which time the prosecution must present sufficient evidence for the case to proceed to district court.