Though it may sound more like a Johnny Cash song , new reports say employees at General Motors Holden plant in Elizabeth, Australia , have been stealing auto parts. Lots of 'em.Police have been investigating the crime spree since January and say engines and transmissions worth more than $2.5 million have been stolen from the plant. The engines, meant to power VE Commodores (formerly known as the Pontiac G8 in the States) sell for $10,000 each through Holden dealers. The stolen engines, however, were going for as little as $1,500 on the black market, and some of the ill-gotten parts have been traced to off-road racing in other parts of Australia.The key factor that allowed the thieves to go undetected popped up pretty soon after the first stolen engine was found by police. Sources say factory officials had no idea employees were taking the hardware and were unaware of the scale until notified by police. Apparently there was "no effective tracking system" of engines and transmissions at the plant and therefore very little way to check where incoming inventory ended up. Parts were checked in, but there was apparently no way to know what happened to them after that.GM Holden corporate affairs manager Sean Poppitt tells reporters, "It is an ongoing investigation and we are not at liberty to discuss any details of it as yet."