Meanwhile, tensions increased between the Earps and the McLaurys when Cowboys robbed the passenger stage on the Sandy Bob Line in the Tombstone area on September 8, bound for nearby Bisbee, Arizona. The masked robbers robbed the passengers and the strongbox, but they were recognized by their voices and language. They were identified as Deputy Sheriff Pete Spence (an alias for Elliot Larkin Ferguson) and Deputy Sheriff Frank Stilwell, a business partner of Spence's. Stilwell was fired a short while later as a deputy sheriff for Sheriff Behan (for county tax "accounting irregularities").