People in Hull are being warned to keep doors locked at all times following a spate of car thefts linked to a series of house burglaries where thieves just stole car keys.
Thieves who stole BMWs, Audis and Mercedes cars from outside homes in the city often just walked in through "unlocked front or back doors", police said.
Det Insp Simon Vickers said: ¡°In recent weeks we've had a number of cars being stolen following the house being broken into.
"In many cases the only thing to have been stolen from inside are car keys. The keys are then used to steal the cars from outside the premises.
"In a number of cases offenders have entered houses through unlocked front or back doors," he added.
The Humberside force said many of the burglaries had taken place between midnight and 04:00, but some had happened "in the late afternoon as it begins to get dark".
Officers have issued a warning to people to keep doors locked at all times rather than locking them before going to bed.
Det Insp Simon Vickers said: ¡°People may not think to lock their doors during the early evening, but I would advise to lock your doors at all times."