The Las Vegas shooting on October 1st, 2017 was the deadliest shooting in modern American history, leaving 58 people dead and over 500 people injured.

About two weeks later, Fr. Clete Kiley from Chicago arrived in Las Vegas with a group meant to help and comfort the traumatized staff of the Mandalay Bay Hotel, from where the killer had opened fire on the concert crowd outside.

He had just finished leading prayer with several hundred members of the hotel staff when the hotel manager approached him. She explained that the shooter’s room had just been released back to the hotel by the FBI, and she wanted him to perform a blessing in the space.

As soon as he set foot in the hallway of the 32nd floor where the room was, he says he immediately felt a dark spiritual presence.

“I felt like I was being pushed back, like ‘don’t come in here,'” he told Newsweek. But he pushed on anyway: “On the inside, I’m going, ‘Oh no, you have to go.’” So he started praying the Prayer to St. Michael.

“When I stepped in the room, I really felt a real profound silence,” he later explained. “I immediately noticed the broken windows covered from outside. It was very powerful to see the physical damage.”

He could sense an evil presence in the room, so he used a palm branch to disperse Holy Water while praying to the Holy Spirit.

Right away, he could feel a sense of comfort and relief. When he returned back downstairs, the hotel staff was also relieved that a Catholic priest had blessed the room.

“You could see people go, ‘Thank God, that’s good,’” he said. “I really saw the whole thing as part of a healing process. A small part of a healing process.”

[See also: Las Vegas Survivor Says Ordeal Turned Him from Agnostic to Believer in God]

[See also: St. Teresa of Avila’s Demonic Experience that Proved the Power of Holy Water]