Vintage musical instruments are being used to help keep tabs on people, even as a growing number of them have become obsolete.
The research, conducted by the National Institutes of Health and the University of Pennsylvania, says some vintage instruments are now used for tracking people and animals.
It said the instruments have been used for years to help track suspects in traffic stops, and that the U.S. Supreme Court has upheld use of the instruments in domestic disputes.
Researchers in the United States and Europe said that although some of the old instruments are still useful, they are also vulnerable to misuse, including overuse, by people with psychiatric illnesses, criminal convictions and even accidents.
They also noted that there are no known uses for the instruments except to help identify suspects, and they are not a good source of information for police because of the difficulty of tracking people.
The new research, published online this month in the journal Proceedings of the National Academy of Sciences, examined the use of acoustic devices in about 500 cases from two U.s. cities.
It found that while some of them had been used in recent years for surveillance of people, some of these devices were used in cases where they had no clear evidence of crime.
It found that one in four of the devices used for these purposes were used to record voices, and one in five were used for monitoring people’s movements and health.
The researchers did not determine whether the devices were also used for spying on people.
They say it is possible that some of their use could have been legal or not.
The report says that many of the older instruments were designed to record conversations, so that police could listen in to them, without knowing the conversation was recorded.
It is possible, however, that people might have mistaken them for recordings of conversations with friends or loved ones, researchers wrote.
In a statement, the National Institute of Standards and Technology, which is part of the U,penned: “These instruments were used long before the advent of video conferencing, and have long been used as a tool for recording conversations, especially in a large number of criminal cases, where recording a conversation in real time was necessary.”
It said that many older instruments had been found in crime scenes or on property.
It said they may have been accidentally damaged or even stolen, and so it is not surprising that the technology may have deteriorated.
It said there is no known use for the technology in domestic conflicts, but it was common for older instruments to be used in situations where there was no evidence of criminal activity.
The U.penn wrote that in the past, law enforcement agencies used the devices to track suspects, especially criminals and fugitives.
In many cases, they would use them to track the suspects as they fled from police, or to make identification with them.
They could also be used to identify victims, if the suspects had been killed.