STOCKBRIDGE, Ga. -- A suspect is in custody in connection with an armed robbery at Krystal restaurant, that left a Clayton County police officer and restaurant manager shot.

23-year-old Marquet Donald, a former Krystal employee, was arrested Thursday around 11 a.m. The suspect's father turned him in to authorities.

The gunman entered the Krystal in the 3500 block of Highway 138 Wednesday night when an employee taking out the trash propped open the back door.

"The gunman demanded that the manager go into the office and hand over the money from the safe," said Clayton Police Chief Jeff Turner.

Police said the gunman then instructed the other employees to walk to the rear of the store, enter the cooler, and place their cell phones into a bag. The employees were not harmed.

When authorities arrived on scene, they found the store manager, 49 year old Cheryl Alphabet of Conley, lying in the floor of the walk-in freezer with a bullet wound to the head.

Police said the manager tried to grab the robber's gun.

"A shot was heard," said Turner. "The manager was shot in the head."

The manager was transported to Atlanta Medical Center where she was in critical condition Thursday morning.

A Clayton County police officer arrived at the Krystal just as the gunman took off in the manager's red Pontiac Sunfire.

During a chase the robber jumped out of the car and began wrestling with Officer Matthew Whitton, a 6-year veteran of the Clayton County Police Department. An altercation involving the officer and the suspect resulted in a struggle for the officer’s service weapon.

The officer was able to maintain possession of the weapon however, received a single gunshot wound to the left wrist during the incident. The suspect escaped on foot. Officer Whitton is in stable condition and is expected to recover.