MEXICO CITY (Reuters) - A two-time Mexico City “policeman of the year” has been arrested on suspicion of extorting money from illegal “car-watchers” who demand tips for curbside parking.

Police said Alejandro Garnino, who was awarded Mexico City’s highest police honor in 2005 and 2006, is suspected of charging up to 1,000 pesos ($94) to allow dozens of car-watchers to operate outside one of Mexico’s largest stadiums.

“It is a shock to all of us. His conduct was such a shining example,” an official at Mexico City’s police force said on Wednesday. He said Garnino turned himself in on Monday night.

Corruption plagues Mexico’s underpaid police forces, where officers regularly take bribes to turn a blind eye to offenses from traffic violations to kidnapping and drug dealing.

In Mexico’s most violent drug hotspots near the U.S. border, President Felipe Calderon has sent the army to clean up police, but army generals say corruption is so deep that cleansing the forces could take years.