In excess of 20 vehicles have had their paintwork scratched following a three-night run of vandalism.
Hartlepool Community Safety Team has been made aware of a series of incidents of criminal damage to motor vehicles in the Foggy Furze area of Hartlepool.
The damaged started on Monday and continued on Tuesday, with further damage caused last night.
The team say more than 20 vehicles - so far - been reported to have been scratched in the areas between Caledonian Road, Westbrook Road, Fernwood Avenue and Oxford Road.
Some vehicles were targeted on more than one occasion over the three nights.
Officers investigating the incidents have been carrying out CCTV enquiries and speaking with residents.
Two girls aged 14 are being interviewed voluntarily in relation to the incidents.
A spokesman for Cleveland Police said: "It is thought that the incidents reported are only a small fraction of those that occurred and that further reports may be received.
"If you have been a victim of criminal damage or if you have further information regarding these incidents, please contact Cleveland Police."
The force can be called on 101 or Crimestoppers anonymously on 0800 555 111 or www.crimestoppers-uk.org.