Officers believe the attacks on the vehicles in Rue de la Croix, St. Clement, took place around 05:00 on Sunday (3 May).
They said that four young people, who were spotted walking in the area of Le Marais towards St. Clement’s School around the time of the damage, may be involved.
Anyone living in the area with CCTV is now being urged to come forward, as they may be able to help identify those involved.
Islanders with footage or more information should call Police on 612612 or make an anonymous report using Crimestoppers’ online form.