Thieves fled with cash after breaking into a string of parked taxis in Crawley.
Police received nine separate reports of vehicles being broken into overnight on March 15 and 16 in the Southgate area.
A spokesman said: “Cash was stolen from five of these vehicles and it is believed the incidents are linked.
“All lines of enquiry, including any CCTV footage, will be investigated.
“If anyone saw someone acting suspiciously in this area please report online (https://www.sussex.police.uk/contact-us/report-online/) or call 101 quoting reference 204 of 16/03.”