The man kept almost 300 tramadol tablets and a sharp-charged weapon in a public space in an apartment building in Umeå.
The police had for a month had a secret video surveillance where they observed when the man opened an inspection hatch in the wall where the weapon and drugs were then found.
The police were then able to arrest the man after they secured information from the surveillance film.
Threat to official
The 20-year-old is also sentenced to a threat against an official after threatening two prison guards to injure and beat them on a visitation occasion.
In the police's preliminary investigation report, the man denied all crimes.
The man is sentenced at Umeå District Court, to prison for one year and eight months.