Police are asking for the public's help in identifying a man who robbed a Bevo Mill White Castle at gunpoint on December 22.Images released by the St. Louis Metropolitan Police Department show the suspect walking into the store at 4524 S. Kingshighway, just south of Chippewa. Police say he brandished a black handgun before leaping over the counter, ordering the cashiers to open the register before helping himself to its contents.…