The mayor of Elizabeth, N.J., said he believes a traffic stop led to a search warrant that brought police to the city to conduct raids.

“I’m not aware of the evidence that led them here, except for the traffic stop that occurred outside of the Verrazano Bridge. That traffic stop led to a search warrant, which brought them to this location,” Chris Bollwage said during a press conference Monday the morning after pipe bombs were discovered outside the city’s train station.