Sgt. Eric Janik, 37, was charged with assault and reckless endangerment for pointing his service handgun at the worker, who was dressed as Leatherface, the killer from "The Texas Chainsaw Massacre," Baltimore County police said.
The employee, Mike Morrison, followed Janik and several other people up a staircase Sunday night at the end of the haunted house tour in a bid to get "one last scream" out of them, police said.
When the group exited into a parking lot, Janik pulled his gun and pointed it at Morrison from less than 10 feet away, according to police and Morrison, who said he dropped the chain saw, put his hands up and backed away. The saw had no chain.
Only then did Janik identify himself as a police officer, said Morrison, who retreated into the building.
"I started shaking pretty bad," he told The Associated Press.
Another employee of the House of Screams called police.
According to charging documents, Janik smelled of alcohol and told police two different stories about what he did with the gun. First, he denied drawing the weapon, but later he said he pointed it at the ground.
Morrison and two other witnesses told police that Janik pointed the gun at Morrison's chest.
Janik had no listed number and a voice mail for his attorney, Shaun Owens, was not immediately returned.
A security guard had been following Janik's group, which included his 9-year-old daughter, through the haunted house because Janik appeared to be drunk when he arrived, House of Screams owner Tony Sapanero said.
Morrison said Janik's daughter appeared to be disturbed by his act, in which he pretends to cut one woman in half and disembowel another with the chain saw.
Janik was suspended with pay after police commanders learned of what happened and could be without pay after a hearing Tuesday morning, city police spokesman Anthony Guglielmi said.
City police officers are required to carry their service weapons while off duty within city limits and can carry them at their own discretion outside the city, Guglielmi said.