POSTED AND FIVE DEED IN KILLINGSCounty Offers S500 and Transit Firm $1,000 inCar Barn Murders.FOUR MEN AND WOMANQUESTIONED IN CASEFootprints. Bullets and GunShells Only Clues Found to Hold-up Slayers.Reward totals were raised to $1,500for information leading to the arrest and conviction of the person*- guilty ; of the brutal killing early yesterday of two Capital Transit Co. employes snd robbery in the car barn office at Chevy Chase. Md . a few miles north ol the District line.At the same time police revealed they had four men and a woman under arrest in connection with the crime.