A suspected robber who lost patience when a clerk couldn't open the cash register was arrested Saturday after he grabbed the entire cash register and ran out the door.

Salt Lake County deputy sheriffs said the man entered Miniature Market, 310 E. 3300 South, about 2:30 a.m. While the clerk was ringing up a package of meat the suspect had selected, the robber came up behind him and put a large kitchen knife to his throat and ordered him to open the cash register.The clerk, apparently flustered, tried to open the register but couldn't. The robber became frustrated, threw the clerk to the ground and then picked up the cash register and ran out the door with it, a sheriff's report stated.

Deputy sheriffs located the register half a block away from the store - the cash drawer still unopened. The man was spotted in the area running behind some bushes, where he was apprehended. The clerk identified the man as the robber, the report said.

A 26-year-old Magna man was booked into the Salt Lake County Jail for investigation of aggravated robbery.

Another robbery occurred about the same time at a 7-Eleven store, 1280 W. 12600 South. The suspect entered the store, wielded a black revolver and ordered the clerk to give him money from the cash register. He then fled with about $60 worth of cash and groceries.