Mahoning Township police are continuing their investigation into the armed robbery of two security guards at the Food Lane, located in the Carbon Plaza, last evening. The amount of cash taken in the theft has not been determined, police said, but the two guards were held up as they left the store with a partial night's receipts en route to a night depository. The robbery took place at about 7:45 p.m. in the employees' parking lot. Police said the gunman was wearing a dark ski-type mask.