LINCOLN -- The search for an armed robber continues, after a hold up just after 9pm Tuesday at the Casey's near 13th and "E" Streets. Lincoln Police Officer Katie Flood says the suspect walked in with a knife, demanding money. At one point, according to Flood, the robber threatened to kill one of the clerks before taking off. Only description police have of the suspect is a mixed-race male, about 6-feet tall with a muscular, but slender build and wearing dark clothing. Almost the same as the suspect in the Sept. 4 Casey's robbery at 40th and Adams, who was described as a light-skinned black male, between 5'10 and 6 foot tall and from 150 to 175 pounds. Officer Flood says they're investigating to see if both robberies are connected.