Serial shopping trolley thief
The 37-year-old man is thought to have stolen 290,000 euros' ($390,000) worth of trolleys which he sold on as scrap, Madrid police said in a statement.
Police attached the tracking devices covertly to several trolleys after being alerted by several supermarkets in the city which reported losing more than 3,000 trolleys this year.
"A GPS positioned on one of the trolleys chosen at random alerted us to its departure from the premises of the establishment and led officers to the suspect," the statement said, naming him only as Juan Antonio R.C.
"It is the first time we have seen such a thing, with such a volume of thefts,"
A police spokesman who asked not to be named told AFP.
He said the man was suspected to have stolen at least two trolleys a day and sold them to a scrap metal dealer.
"It was clearly a lifestyle for him. He did it every day, as a full-time profession."
Police said the shops estimated at some 290,000 euros the overall value of the stolen trolleys, which they buy for between 80 and 200 euros each.