The vehicles are submerged in several northwest suburban ponds, put there by members of an auto theft ring that is the subject of an investigation by Illinois State Police and a DuPage county task force known as BATTLE, the acronym for Beat Auto Theft Through Law Enforcement.
Police say they can't reveal any details because the investigation is under way.
More than 20,000 cars are stolen every year in metro Chicago, some even towed away by the thieves. Police say 17 of them have been found sunk in northwest suburban ponds.
Authorities were just alerted to the vehicles after they were spotted from the air by a state transportation department doing aerial survey work.
Tuesday afternoon, state and DuPage County auto theft investigators supervised dive teams that began underwater inspections of the cars. Police tell the I-Team that they are first pinpointing the locations of the vehicles so they can be raised from the water and processed.
A crime scene perimeter was set up on the South Barrington and Hoffman Estates border Tuesday as investigators plotted where the cars are and the conditions.
Even though Illinois has a significant car theft problem, the number of stolen vehicles in the state has fallen dramatically since 1991, according to the latest data. In 1991, more than 75,000 vehicles were stolen statewide. The most recent record: A little less than 27,000. That is a decline of 64 percent.
Cook County accounts for most of the thefts. Last year, 19,896 vehicles were stolen in the county. That is almost three-quarters of the state total.
Police say 60 percent of all stolen vehicles are recovered in some state of disrepair.
The 17 that are submerged in the suburbs won't do their owners any good, but may help prosecute whoever put them there.
Police say there is no schedule yet for recovering those underwater cars. It also isn't clear tonight why DuPage County is the lead local agency on this case, considering that the ponds are in Barrington, which isn't in DuPage.