VERO BEACH, Fla. (AP) _ Domino's Pizza offered a $10,000 reward Wednesday in the slayings of two employees who were found shot in the head and dumped in a back room of the restaurant.

A third employee was critically wounded in the apparent robbery Tuesday night at the downtown take-out pizzeria.

Police investigators say they have few clues and no witnesses.

''We're working as hard as we can following up on everything we've got,'' said Deputy Police Chief Roland Wood. ''The trouble is we don't have too much to go on right now.''

An undetermined amount of money was found missing from the cash register and there were no signs of forced entry into the store, which was just two blocks from the police station, said Police Chief James Gabbard.

''The way they were shot leads us to believe more than one person was involved,'' he said.

To help in the search for suspects, Domino's offered the reward for information leading to a conviction, and sent four of its crime-prevention investigators to the scene, said Ron Hingst, a spokesman for the Ann Arbor, Mich.-based pizza chain.

''It's a tragedy when something like this happens because we try to take every precaution,'' Hingst said. ''We ask that back entrances be locked, we have a time-delayed safe and we don't keep that much money around.''

Investigators have not had a chance to interview victim Matthew Boornoosh, 27, who was in surgery overnight for the head wound and remained in critical condition Wednesday at Indian River Memorial Hospital.

Killed were Domino's management-trainee Bill Edwards, 27, and his wife, Frances, 29, employed as a driver at the store, the chief said.

The bodies were discovered about midnight when Dan Lawing drove to the store after waiting more than 45 minutes for the delivery of his pizza.

''The front of the store was dark, but you could see lights on in the back,'' said Lawing, 29. ''The door was open, so I just poked my head in and yelled 'hello' a couple of times. I knew something was wrong, so I got the police.''

''My heart's still beating,'' said Lawing. ''I just keep thinking that if I had gotten there just a couple of minutes earlier, that could have been me shot.''