A North Mankato man is arrested after causing a stir for riding around Mankato with an assault rifle on his back.Mankato Public Safety arrested 25 year old Justin Lietha (Lee-tha) shortly after 10:00 last night.Police say he was riding his bike down Riverfront Drive with an SKS semi automatic assault rifle on his back.The weapon's magazine was empty.Lietha did not have a permit to carry and was arrested for carrying a rifle in public and disorderly conduct.