The St Albans district has been targeted with 17 catalytic converters thefts this month.
Precious metal contained in catalytic converters make them tempting for thieves and the St Albans district has been heavily targeted.
To get to the catalytic converter, which are fitted to the exhaust system, thieves need to get underneath the vehicle or jack it up.
“With more people continuing to work from home, activity by your neighbours’ car may seem out of place,” said St Albans district Detective Inspector Ady Lysak.
“If you have your suspicions about activity near vehicles – especially Toyota, Honda and Lexus makes – please let us know so we have every chance of catching the thieves in the act.
“We would also be interested in any doorbell or dash cam footage of thefts. The good news is there are some things you can do to help make your vehicle less attractive to an opportunist thief.”
Catalytic converters from a Toyota Yaris and a Toyota Prius were stolen from an address in Trumpington Drive at 8.40pm on November 20. Four men in balaclavas were seen at the time.
Catalytic converters were stolen from a Mazda on November 12 and a Lexus on November 10, both from Admirals Close in London Colney.
A catalytic converter was stolen from a Lexus parked in Wellington Road between November 9 and November 11.
You can find techniques to protect your cars by going here.