Fitbits, pacemakers, Amazon Echoes – all are tools of the modern detective’s trade in a world where our devices are always watching

Richard Dabate told police a masked intruder assaulted him and killed his wife in their Connecticut home. His wife’s Fitbit told another story and Dabate was charged with the murder.

James Bates said an acquaintance accidentally drowned in his hot tub in Arkansas. Detectives suspected foul play and obtained data from Bates’s Amazon Echo device. Bates was charged with murder.

Ross Compton told investigators he woke up to find his Ohio home on fire and climbed through a window to escape the flames. Compton’s pacemaker suggested otherwise. He was charged with arson and insurance fraud.

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All three men, besides pleading innocence, have one thing in common: digital devices may help put them behind bars and etch them in criminal history as some of the first perpetrators busted by the internet of things.

Plenty more will surely follow because the connected devices we use for convenience, entertainment and health can also contradict our alibis and expose our lies.

Smart cars, fridges, doorbells, watches, phones, Fitbits, sneakers, televisions, gaming consoles, coffee makers, pacemakers – a fast proliferating list – all can monitor, record and be used as evidence.

“I think everyone realises – good guys, bad guys, cops, robbers – that everything is being videotaped or tracked somehow,” Andy Kleinick, the head of the Los Angeles police department’s cyber crimes section, and a supervisor for the secret service’s LA electronic crimes task force, said in an interview.

Facebook Twitter Pinterest Andy Kleinick, head of LAPD’s cyber crimes section. Photograph: Rory Carroll/The Guardian

“The internet of things has been explosive. We are being tracked all the time. If you don’t know that, you’re crazy.”

Columbo, the shambling LAPD TV detective played by Peter Falk, snared suspects through guile and doggedness. Still useful attributes, but digital troves give his real-life descendants an extra edge.

“Is it more difficult to commit a murder? I’d imagine yes. We do a lot of homicide cases where people leave a lot of information – researching how to get rid of a body, or googling poison,” said Kleinick. You could do your research on a library computer, he said, but it won’t do much good. “They track it too.” Vehicle navigation devices can also act as silent witnesses, recording turns, pauses and stops.

Kleinick and his team give courses to cops and detectives in how to handle digital evidence and what to look for at crime scenes – a games console, for instance, can contain chat messages and child abuse images.

“We can’t keep up with the demand. Soon I’ll be teaching full-time because the [LAPD] chief wants everyone to have some form of cyber-training,” said Kleinick, 56, a maths whizz who worked for IBM before joining the force three decades ago.

The old timers who don’t understand cyber are mostly gone, and new recruits, digital natives, adapt easily, he said. However, it takes a special breed to work full-time in the cyber crimes section.

“I want someone who is happy sitting for 10 hours a day examining bits of data. Some people go crazy doing that, some love it. We know right away if they’ll make it because if they don’t like it they pull their hair out.”

Detectives across the US are learning the value of connected devices.

Richard Dabate claimed a would-be burglar beat him and shot his wife, Connie, in their home in Ellington, Connecticut, shortly before Christmas in December 2015. But she was wearing a Fitbit that showed her walking 1,217ft around the house well after the time her husband said she was shot.

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When detectives checked her phone they found a list titled: “Why I Want a Divorce”. Dabate’s murder trial is pending.

Police in Bentonville, Arkansas, suspected foul play in the November 2015 death of Victor Collins, who went to the home of James Bates to watch a football game and wound up dead in a hot tub.

Bates had several internet-connected devices, including a Nest thermostat and Amazon Echo. The Echo responds to voice commands and streams audio to the cloud, including a fraction of a second of audio before its “wake word”.

Amazon initially resisted a police request for Echo data, citing the first amendment, but relented after Bates approved the handover. Its relevance in the case is unclear. Bates’s smart water device may also yield clues. It recorded 140 gallons of water use during the early hours of the night in question. Bates’s murder trial is also pending.

Ross Compton said he was sleeping when his house in Middletown, Ohio, caught fire in September 2016. He said he grabbed some possessions and jumped out a window. Investigators pulled data from his pacemaker which, according to a cardiologist, undermined Compton’s account. He has been charged with aggravated arson and insurance fraud.

Public awareness has yet to catch up with the ubiquity and implications of connected technology.

Ring, an LA-based start-up, has sold about 1m video doorbells which connect to smartphones and wifi networks. Jamie Siminoff, the company founder, showed the Guardian a video of a woman and a male companion ringing a bell in Monrovia, California, and then trying the handle. The absent homeowner, watching remotely, challenged them through the speaker. Startled, they fled.

The homeowner notified police who nabbed the couple, with a third person, at a traffic stop. The woman had an outstanding arrest warrant and was driving with a suspended license. The car contained a loaded gun and ounce of heroin.

Facebook Twitter Pinterest Jamie Siminoff, founder of Ring. Photograph: Rory Carroll/The Guardian

But Brian Jackson, a criminal justice scholar at the Rand Corporation, said some police departments, especially smaller ones, struggled to keep pace with the technology. The US has more than 18,000 law enforcement agencies, not all able or willing to grasp the opportunities, he said. “It’s very uneven and early in the adoption curve.”

He also warned technology was outpacing debate over privacy. “The general public isn’t aware of the full capabilities. It’s a symptom of our love of technology and lack of detailed skepticism.”