YOKOHAMA - A man prowling through a vacant house in Japan was caught on camera as he searched the darkened rooms by the light of his smartphone. Even after spotting the camera and turning it away, he could not escape the evidence it had already recorded.
The incident in Sagamihara, Kanagawa Prefecture, in August highlights how affordable home monitoring cameras are emerging as a security tool, particularly for vacant properties that are increasingly being targeted by thieves.
Commonly used to check on elderly people, children and pets remotely, the devices are generally cheaper and easier to install than conventional security cameras, allowing users to monitor their properties through smartphones and other devices.
In the Sagamihara case, footage showed the intruder moving around the house before noticing the camera and adjusting its angle to avoid being filmed. He then continued searching the property.
Although the camera was believed to have been taken, its footage had been saved online, allowing police to identify the suspect. The man was arrested in September and later charged with trespassing and attempted theft.
"The footage gave us a lead in the investigation and provided clear evidence of the crime," a senior Kanagawa prefectural police investigator said.
The case comes amid a sharp rise in thefts targeting vacant homes across Japan.
According to the National Police Agency, reported cases have increased for five consecutive years, jumping more than fourfold from 3,425 in 2020 to 13,971 in 2025.
A senior prefectural police official said the growing number of vacant properties was one factor behind the increase, with burglars potentially viewing unoccupied homes as easier targets because they are less likely to encounter residents.
Hiromu Fujimitsu, secretary general of the Fukuoka Prefecture Security Equipment Specialists Association, said the most effective deterrent was to make a property appear occupied.
He also stressed the importance of making security measures visible, saying cameras and other equipment should be installed where potential intruders can easily see them.
Amazon Japan, which markets the Ring brand of cameras used at the Sagamihara property, said demand for home security applications was growing, with interest now comparable to that for monitoring pets or checking deliveries.
Yusuke Seguchi of Amazon Japan said their appeal lay partly in smartphone connectivity, which allows users to "detect a problem, check what's happening and respond without interruption."
Experts say the cameras could also be useful in small shops and offices, offering a relatively simple alternative to more elaborate security systems.
But their growing use has raised concerns about privacy and the possibility of personal data being leaked, particularly when cameras are installed inside homes.
Yohei Fukumizu, a Ritsumeikan University professor specializing in image analysis, said affordability was a major advantage, allowing users to install several cameras and choose functions suited to their needs.
He said advances in artificial intelligence could further expand what the devices are capable of doing.
