Two men in ski masks stole several items from an Arlington County fire truck last week, including a set of keys owned by the Metro system, Arlington County police said.

Arlington Police spokesman Dustin Sternbeck said the crew was treating a patient in the 500 block of South 15th Street when the incident occurred.

The theft was first reported by NBC4 Washington.

Metro spokesman Dan Stessel said Tuesday that officials there “do not believe our property was the target.”

“For security reasons we would decline to publicly disclose what the keys provide access to,” Stessel said. He said Metro Transit Police have “taken appropriate steps to ensure that system security is not compromised.”