A distraction burglar posing as a council contract worker is targeting the homes of the elderly and vulnerable.
Sussex Police is warning people in Brighton and Hove to be on their guard following five incidents in the past two weeks.
The man, who wears a sweatshirt or t-shirt with the logo of contractors Mears on it, has been calling on houses in the early to mid-evening, saying he is working for Brighton and Hove City Council.
Having gained the trust of the occupant, he then takes the opportunity to steal from the property.
Detective Inspector Vicki Harris said: "We know that this type of crime is a problem at the moment, but this man is a particularly despicable character.
“As well as wanting to catch him, we really want to get the message out to the city's elderly and vulnerable residents not to be taken in by him.
"It is also important that relatives and friends who have family members or neighbours who may be at risk warn them and watch out for them.
"Unless you are expecting a visit from a council official, someone representing Mears or indeed, any other person, please don't let them in.
“Any bona fide caller will be happy for you to check with their organisation, but check their main telephone number yourself - don't call a mobile number that they provide you with.
"If you have been targeted by someone in this manner recently and you have your suspicions about them, please call us on 101 or if they're at your door or in the area now, please dial 999 immediately."
The man is described as white, in his early to mid-20s, 5ft 8in to 5ft 10in, slim, clean shaven with fair hair and wearing dark rimmed glasses.
A Mears spokeswoman said: All of our operatives will make an appointment before calling and will never turn up unannounced.
"They have to carry an identity card and show it. If you want to check that they are genuine, you can call our contact centre on 0800 052 6140."
The most recent incident was at a home in Manor Green at about 8pm when the man stole several hundred pounds from a bedroom.
He had told the elderly resident he had come to measure up for a bath.
Anyone with information is asked to call Sussex Police on 101 or email firstname.lastname@example.org quoting Operation Dolphin.