An Arlington County police officer caught three alleged thieves red-handed when they opened an unlocked car early Wednesday morning — and found the officer hiding in the back seat.

Police officers launched a plainclothes surveillance operation Wednesday in response to a rash of recent thefts in the Shirley Park area of Arlington, according to Lt. Michael Watson.

Officers observed three men entering 21 unlocked cars and taking items from the vehicles in the 1800 block of South 28th Street around 1:30 a.m. Wednesday, Watson said.

Hilary Edmond, 22, of Arlington, and Robert Holt, 18, of Alexandria, were arrested immediately. Enrique Vanterpool, 23, of Alexandria, fled the scene, but was found hiding under bushes by a police dog, who bit the suspect to restrain him.

Vanterpool was treated at the scene, Watson said.

The men were charged with entering a vehicle, petit larceny and buying or receiving stolen goods, according to court records.

Edmonds and Vanterpool were still in custody as of noon Thursday, according to court records. Holt, who also is charged with possession of marijuana, is out on bail.

Watson said the police officer hiding in the car was conducting surveillance, not trying to set up the suspects. Police are investigating other previous thefts to see if they can be linked to the suspects, authorities said.