DES MOINES, Iowa (AP) — A Minnesota teenager has been sentenced to life in prison for the shooting death of an Iowa convenience store clerk last fall.

Michael Swanson, of St. Louis Park, Minn., was sentenced Thursday in Webster County for the Nov. 15, 2010 slaying of Sheila Myers at the Kum & Go store in Humboldt where Myers worked.

A Carroll County jury found him guilty last month of first-degree murder and first-degree robbery in the slaying.

The 18-year-old Swanson also is charged with first-degree murder and robbery in the death of a clerk at an Algona gas station on the same day. He is expected to plead guilty to those charges later Thursday in Kossuth County.

In Iowa, a life sentence is mandatory with no chance of parole.