SAGINAW TOWNSHIP, Mich. -- Thieves in Saginaw Township are not stealing the whole car, just one valuable part.

In a story that is becoming all too familiar to Mid-Michigan investigators, police are reporting the theft of at least eight catalytic converters from four different Saginaw Township apartment buildings over the weekend.

Some were stolen Friday night into Saturday morning, with two stolen from cars at Green Acres Village apartments, two from Clairemont Village apartments, two from Bayside apartments, and two from Poplar apartments.

This comes on the heels of reports of more than 30 converters being cut from cars in Hampton Township the weekend before.

Police said they believe the thieves are cutting the converters from cars, behind the engine and before the muffler, then selling the converters to scrap yards.

When in pieces, stolen catalytic converters can be sold for about $100.

A local mechanic said it takes a person who knows what they are doing about a minute to cut the auto part from underneath a vehicle.

Police also said apartment complexes are targets because of such a high concentration of cars in their lots.

Over the past six weeks, many 'cats' were stolen from Bay County apartment complexes.

With the hard hit economy in Mid-Michigan, thieves are resorting to scrap metal sales, and catalytic converters contain a combination of expensive metals.

Converters are used to reduce emissions from gas-burning cars and trucks by providing a setting for chemical reactions to occur where toxic combustion by-products are transformed into less toxic substances.

A new converter for a 2007 Chevy Silverado can cost $400 or more to replace.