The US Naval Criminal Investigative Service is investigating after multiple Navy personnel reported receiving unsolicited smartwatches in the mail that could be installed with data-stealing malicious software, an NCIS spokesperson told CNN on Friday.

The news comes after the Army warned publicly this month that “service members across the military” had reported receiving the devices in the mail.

It’s unclear who is mailing the suspicious watches, but the devices are telltale signs of a counterintelligence and cyberthreat. When used, the devices automatically connected to wireless networks and cell phones, “gaining access to a myriad of user data,” the advisory from the Army’s Criminal Investigation Division (CID) said.