Police have reported that about two dozen vehicles were stolen from rental car companies at Maine’s Portland International Jetport, according to a report by News Center Maine.

Over a four-month period, between 20 and 25 vehicles were taken, a majority from Avis Car Rental. Portland Police Department Lt. Robert Martin said it was an inside job: “What we learned was a group of former employees that were stealing cars, identifying cars that could be stolen to friends,” he told News Center Maine.

In some of the cases, the thieves took the vehicles for weeks and shared them with friends while some of the cars were used to commit crimes, including robberies and a couple of car chases, according to Lt. Martin. 

Two arrests have been made so far, according to the report. Most of the vehicles have been recovered in Portland, Westbrook, Scarborough, as well as in the nearby states of Rhode Island and Connecticut.

Police don’t think there’s a safety concern at the airport, but they are working with the airport and its rental car companies to improve security measures, according to the report.