Tyke, an eight-year-old Labrador, at work on a Heathrow carousel. His specialism is discovering animal products / Frantzesco Kangaris

New England is the second state in America to use specially-trained canines to find hidden electronics such as hard drives and USB sticks

Locating hard drives or memory cards containing evidence of child abuse can be difficult for police, but now law enforcement in the US have enlisted specially-trained sniffer dogs to detect hidden electronics.

A new scheme covered by the New England newspaper Providence Journal reports that a police dog named Thoreau discovered a USB stick containing child pornography hidden four layers deep inside a metal cabinet in June. The discovery led to the arrest of thumb drive's owner.

Rhode Island in New England is reportedly the second state in the US to enlist police dogs trained to sniff out electronics, with the Connecticut State Police Training Academy reporting that it takes 22 weeks to bring the canine recruits up to scratch.

Detective Adam Houston, Thoreau’s handler, told local news, “If it has a memory card, he’ll sniff it out,” adding that the dog was rewarded with treats for finding electronics and this was how it ate “every day”.

However, Maggie Gwynne of Sniffer Dogs UK & International told the BBC that this was irresponsible. "Offering a sniffer dog food in exchange for a 'find' opens the way for an abuse of the system - if its hungry enough it will take food from anybody, not just its handler and therefore defeats the object of the search," she said.

Speaking to The Independent, Dave Charlton of Durham Constabulary’s Dog Support Unit said that it may be possible to train dogs to sniff out electronics, but added that it was difficult to pass comment on the efficacy of the methods without a more detailed report.

“You can train dogs for virtually anything,” said PC Charlton. “But there’s a lot of training involved to get them to be competent and efficient  – whether it’s for drugs, cash, bodies, blood or any other item of interest."

Sniffer dogs in the US have become a subject of controversy in recent years, with the Supreme Court ruling in 2013 to limit their use under the Fourth Amendment – the part of the constitution prohibiting unreasonable searches.

Studies have also found that the dogs can be unreliable, with trained canines ‘detecting’ illegal substances only at the prompting of their handler and so giving police “probable cause” to search suspects.