Thieves sawed catalytic converters off seven Chevy Cavaliers parked in a Pittsfield Township apartment complex early Sunday, township police said.

Township police are now asking residents to be on the lookout and report any suspicious activity in parking lots late at night.

The Chevy Cavaliers were parked throughout the Spicetree apartment complex in the 4700 block of Packard Road when the catalytic converters were swiped between 3-9 a.m. Sunday, Detective Lt. Sean McCormick said.

McCormick said it's unclear why Chevy Cavalier vehicles were targeted.

Multiple other catalytic converter thefts have been investigated by Pittsfield Township police in recent months, prompting police to issue an advisory in August on how to prevent such thefts. Among the tips were parking in well-lit areas and close to buildings, if possible.

The theft of a catalytic converter takes less than a minute to commit, as thieves use a cordless saw to cut the exhaust pipes that connect the converter to the vehicle, police said.

In August, several similar thefts occurred in the Glencoe Hills apartment complex off Washtenaw Avenue.

McCormick said residents should be on the lookout for any suspicious people, vehicles or noises — such as the sound of a saw — late at night, especially in large parking lots.

The catalytic converter is used to convert harmful pollutants into less harmful emissions before they leave the exhaust system. It's located in the car's exhaust system, and precious metals such as platinum, palladium, rhodium or gold are used as the catalyst. Police say thieves sell the converters to metal recyclers, who then extract the metal and resell it.

Anyone who sees suspicious activity should call 911. Anyone with information on the thefts is asked to call township police at 734-944-4911.