LOS ANGELES (AP) — The FBI said Tuesday it found no evidence that a bomb threat which prompted heightened security at a Los Angeles subway station was real and the anonymous caller who made it may have reported similar phony threats in the past.

However, Los Angeles police and Los Angeles County sheriff’s deputies remained on “a heightened state of awareness,” FBI spokeswoman Laura Eimiller said in a statement Tuesday night.

Heavily-armed deputies stood watch Tuesday at the Universal Station of the Metro Red Line after a threat that said some event would happen that day.

Mayor Eric Garcetti, who took the commuter train to work from the station as a show of confidence, said the warning was made anonymously to an overseas tip line.