(CNN) Authorities say that more than 100 missing vehicles, including 50 Mercedes-Benz, may have been fraudulently rented through a mobile app in Chicago.

Police were alerted by car-sharing service Car2Go "that some of their vehicles may have been rented by deceptive or fraudulent means" on Wednesday.

Numerous vehicles have been recovered at the West Side of Chicago and more than a a "dozen persons of interest" are being questioned. Police spokesperson Christine Calace said 21 people were charged with misdemeanor criminal trespass to vehicles. One also was charged with felony financial identity theft.

"Currently, 100 vehicles are unaccounted for and it is believed that 50 vehicles, all Mercedes Benz, remain in the Chicago land area," Officer Jose Jara, another spokesperson for the department, told CNN.

Read More