National Police Arrest Jewellery Burglary Gang

This footage shows the syringes, acid and lock-picking kit used by two travelling burglary gangs who corroded door mechanisms from the inside and left threads of glue on frames to work out whether anyone was home.

The footage was obtained from the National Police (Policia Nacional)  and shows searches carried out in the Madrid muncipality of Arganda del Rey.

The video shows officers handling recovered jewellery and watches alongside the tools seized during the raids, including a bottle of nitric acid.

The Policia Nacional said: “Two criminal groups specialised in robberies in homes were dismantled and 32 criminal acts solved.

“Seven arrested, five of them in prison. Seized jewellery, money, and tools.

“They used nitric acid, impressioning, and marked doors with glue thread to detect if there were residents.

“They operated throughout the national territory.”

The first inquiry opened in April 2025 into a four-strong outfit, two men and two women, run from safe houses in Arganda del Rey and the capital.

The two women arranged the properties, vehicles and wider logistics, alternating hire cars with motors registered to front men so nothing could be traced back to them.

While one man waited inside a building to watch residents leave, the other kept lookout in the street, and once a flat was empty they let themselves in using impressioning, a technique that takes an impression of the key and leaves the lock unmarked.

The pair were seized moments after a break-in in the city of A Coruna, carrying jewellery, cash, door-opening tools and a heavy magnet used to stick the kit under the bodywork of their car to defeat roadside checks.

Investigators have tied that group to 18 burglaries, with the two men remanded in custody after the women were held during house searches that turned up a luxury car.

The second gang, based in Sagunto, injected nitric acid into locks to eat away the internal workings so they could be forced with basic tools, a method the force describes as unusual in Spain.

They struck at weekends and during holiday periods, and all three were caught as they prepared fresh raids with a lock already ruined and several flats marked up.

Officers advise using well-signposted indoor CCTV, timers on lamps to fake occupancy, and never leaving blinds fully shut, and urge anyone spotting glue residue or small objects propped against a door to call 091 without touching anything.