It was already dark but the engineer of an Amtrak passenger train passing through Chatsworth Park on Sunday night was certain that he saw a man standing near the tracks pointing a gun at the oncoming train.
Then he saw a bright flash, followed by what sounded like two gunshots.
Terrified that he and his passengers were under attack, the engineer radioed police and stopped the train shortly before 9:30 p.m., checking to see if any passengers had been injured and if the train had been damaged.
Police arrived at the park moments later and spotted a group of young people who appeared to be holding guns.
But the guns turned out to be toy weapons equipped for shooting harmless light beams, not bullets, and the alleged shooters were really participants in an evening game of laser tag, a variant of hide-and-seek in which players "shoot" one another with toy guns, Los Angeles Police Sgt. Ted DeMaegt said.
Police briefly questioned the players and allowed them to leave after determining they had not committed a crime. But seven young people, who weren't playing tag but were found loitering near the tracks, were arrested and jailed on suspicion of trespassing, DeMaegt said.
"They were in an area closer to the tracks, closer to where the problem was" than the laser tag players were, DeMaegt said. "We were just checking everybody in the general area. The area is all fenced with no-trespassing signs, and they were inside the posted area."
The train resumed its trip to Santa Barbara, and authorities lifted a 1 1/2-hour ban on railroad traffic through the park while the investigation was under way.
Arrested were James R. Wilson, 19; Robert P. Wilson; Anthony Nourse, 20, and Christopher Charles, 18, all of Canoga Park. The names of the other three youths were withheld because they are juveniles.
DeMaegt said he did not know what the group was doing near the railroad tracks.