The DEA used AirTag to track equipment suspected of being in possession of drugs.

In short: Trackers like Apple’s AirTags can be a godsend for people who find themselves constantly losing things, but they are also often used for illegal purposes, especially for stalking. Law enforcement officials also use AirTags in ways not intended by Apple, such as tracking the movement of drug manufacturing equipment.

Citing an official search warrant, Forbes writes that the Drug Enforcement Agency (DEA) recently hid an Apple AirTag inside a tablet-compressing machine they believed was for an illegal drug manufacturer, allowing the agency to track his movements as he left China. This is believed to be the first time a federal agency has used Apple trackers for surveillance purposes.

GPS tracking devices have long been available to law enforcement, but they are reported to fail frequently. A source told Forbes that these devices are bulkier and more visible than AirTags, which appear to have more reliable connectivity. The Apple product is also said to be easier to use.

But criminals have a way to detect AirTags. There have been many incidents in which trackers have been used for harassment – a review of police records found that one-third of AirTag incidents involved this crime, leading to a class action lawsuit against Apple. This has led Cupertino to update its iPhones to alert users if an unknown tracking device is found on them. The detected AirTag will also emit noise to determine its location.

The DEA was given permission to monitor the AirTag for 45 days throughout the US. It is not yet clear how useful the device was in the agency’s investigation into the drug manufacturer. The Justice Department confirmed that the recipient of the pill press was indicted in federal court. Assuming the suspect never found the tracker, the DEA will likely use the devices for similar surveillance programs in the future.

Law enforcement may consider using Tile trackers instead of AirTags. The company’s recent Anti-Theft mode prevents them from being detected with Tile’s anti-harassment feature. The idea behind this mode is that it “makes it easier to find stolen valuables as it becomes more difficult for thieves to know that an item is being tracked.” Anyone who uses this feature to stalk faces a $1 million fine.