A D.C. police officer chased a robbery suspect onto Metro, only to find himself stranded with the armed man and unable to call help.
The emergency intercom located inside the train didn't work, police say, and both the officer's radio and cell phone were without signal.
Metro said this is the first time they've heard that the emergency intercom found in every train car didn't work.
Police had issued a lookout for a suspect who had robbed an Italian restaurant on Oct. 16 around 9:30 p.m.
An officer saw the suspect at the U Street-Cardozo Metro station. He followed him onto the train and tried to use the emergency intercom to call help, but sources say the intercom didn't work despite multiple attempts.
According to sources, the officer was able to handcuff one of the suspect's hands to a metal seat railing as the suspect was struggling against the officer.
Sources say the officer pressed the intercom at least two more times to no prevail. The officer found a gun on the suspect, which later turned out to be a BB gun.
He travelled with the armed suspect for six stops until he was able to get a cell phone signal at the L'Enfant Plaza station, where he called 911. At the next stop, help arrived.
A Metro Transit Police spokesperson said he had not heard reports of an intercom not working but said Metro will look into the issue.
Metro has cell phone service at 20 of the busiest stations. Other stations will be equipped by 2013.
The alleged robber is wanted for multiple robberies in the area. The D.C. police officer received an award from the police chief for his work.