(Portland, OR) -- A cannabis store employee is pleading not guilty to first-degree murder after allegedly shooting three men who were robbing his shop at gunpoint, killing two of them. KATU-2 reports 34-year-old Jason Steiner pleaded not guilty in court yesterday. Steiner had previously pleaded not guilty to two counts of second-degree murder, but the charges have since been upgraded. Court documents state Steiner was working at La Mota marijuana dispensary in North Portland last October when three men entered the store and used guns to rob him. The suspects reportedly let him leave the store, at which point he allegedly walked to the drive-up window and fired his gun until it was empty. Two men were killed, and a third man ran from the scene.