IDIOTS are breaking into cars and sending them careering down hills in Huddersfield.
The cars have smashed into walls, other vehicles, trees and lamp-posts.
If they hit someone and kill them those responsible could face a murder charge.
The highly dangerous craze has surfaced out of the blue with eight cars sent down steep hills since Saturday night.
The attackers smash windows to get into the vehicles and release the handbrakes.
The resulting damage is already running into many thousands of pounds.
Now a special police squad from Huddersfield CID has been set up to catch the culprits.
Det Insp Ian Devey said: "What these criminals are doing is absolute madness.
"They have absolutely no control over the car once they've let it go. If these vehicles hit a pedestrian or another vehicle and kill someone there will be strong grounds to pursue a murder charge."
The cars pick up such speed they could smash through garden walls and crash into homes.
Det Insp Devey added that the offences the culprits have already committed include aggravated vehicle-taking and criminal damage.
The first car was attacked in the early hours of Sunday morning and the offenders have struck every night since then - always between 2am and 3.30am across Huddersfield.
Det Insp Devey added: "They are looking for cars which will roll the furthest - usually those near the top of a hill with nothing else in front of them.
"They have struck all over Huddersfield, which makes us think they are travelling around in a car.
"More than one person may be involved in this and it is vital someone comes forward with the names of those responsible before someone gets badly hurt or even killed.
"This has got to stop now. Anyone with an ounce of common sense can see the potentially horrendous consequences of what could happen."
Police patrols across the areas targeted so far have been stepped up, but people who park their cars on hills have been urged to use their steering lock and also turn the front wheels in towards the pavement, so if their car is attacked it should turn to the side rather than careering down the road.
Cars targeted so far include a new VW Bora, a Renault Laguna, a Ford Fiesta and a Citroen AX.
The eight incidents have happened on Kaye Lane, Almondbury; Gawthorpe Lane, Lepton; Primrose Hill Road, Newsome; Lockwood Scar, Newsome; Blackmoorfoot Road, Crosland Moor; Cockley Hill Lane, Kirkheaton; Fenay Bridge Road, Fenay Bridge, and Lascelles Hall Road, Kirkheaton.
Contact Huddersfield CID on 01484 436685 or Crimestoppers on 0800 555 111.