It just took less than one minute to trick the vehicle's systems to think that the key is present and subsequently unlocking it.
Two thieves have been filmed using signal amplifiers to steal a Mercedes by tricking it into thinking that they had the keys.
Released by the West Midlands Police Department on Monday, authorities believe it to be the first footage of thieves attacking a vehicle using relay boxes, devices that can be programmed to send signals through walls. The result is that the thieves can open a vehicle, start it, and drive away - all while the keys sit inside the sleeping owner's house. It shows the two men arrive at the home in a auto before one of them approaches the front door with a relay box.
Video footage released on November 26 taken at a home in Solihull in the west of England, shows how the method relies on two people.
Sergeant Tim Evans of Solihull Police said: 'It's important the public are reassured that we are taking proactive steps to tackle this type of crime in Solihull. As part of the tactic, one person holds a relay box as close to the key fob as possible - the signal can be picked up through walls - while another person holds a box next to the vehicle.
'It is always worth speaking to your main dealer, to ensure that your vehicle has had all the latest software updates and talk through security concerns with them'.
How can it be prevented?
The technology picks up the signal from the car's keys - which were inside the house - and repeats it.
The "relay" method can also be thwarted by a metal box.
Cars with manual ignitions can not be started via the use of a relay box. While this may seem like an extreme solution, relay theft is an extreme practice'.