Two Los Angeles County sheriff's deputies said they made contact with a man who was peeing in a planter outside the station around 9:20 a.m. He was then arrested and authorities discovered the weapons in a duffel bag.
Inside the bag was a loaded AR-15 rifle, two loaded 30-round magazines, loaded .40-caliber handgun with an extended magazine, silencers, machete, rope, several rounds of ammunition and a notebook with "unidentified writings."
The suspect, identified as 28-year-old Christopher Harrison Goodine, of Union City, Georgia, was booked into the East Los Angeles sheriff's station in lieu of $50,000 bail.
During a press conference, Sheriff Jim McDonnell said there was no intelligence that indicated Goodine was linked to terrorism, but said regardless the outcome could have been devastating.
"But for the grace of God, we could have had a tragedy today in Los Angeles," he said.
Deputy Katherine Zubo, who was one of the deputies that detained Goodine, said she felt relief that they found the bag before anything could happen.
She said Goodine was verbally compliant with the deputies, but provided them with a false name.
Initial investigations indicate Goodine boarded a train at a Chinatown station and got off at the Sierra Madre location, but Zubo said it was all still under investigation.
Authorities said there was nothing unusual about Goodine's appearance or actions other than what he was initially stopped for.
The investigation was ongoing.