A custodian at Brown University reported witnessing the shooting suspect numerous times in the weeks preceding the December 13th campus attack, even notifying a campus security officer about his observations.

Derek Lisi shared with The Boston Globe that he had seen a man frequently pacing the corridors of the Barus and Holley engineering and physics building. The individual appeared to be scrutinizing classrooms and even concealed himself behind a bathroom on one occasion to avoid detection. The tragic incident on December 13 resulted in two fatalities and left nine others injured. Currently, five victims are hospitalized at Rhode Island Hospital and are in stable condition.

Upon the release of images of the shooting suspect by law enforcement, Lisi immediately recognized the individual, stating, “He’d been casing that place for weeks.”

Lisi disclosed to the media outlet that from early January, he had encountered a man resembling the suspect described by police, identified as 48-year-old Claudio Manuel Neves Valente, approximately ten times.

In a photograph taken on December 21, 2025, in Lincoln, Rhode Island, Derek Lisi, the Brown University custodian, is seen recounting his encounters with the alleged shooter. (Matthew J. Lee/The Boston Globe via Getty Images)

“I knew there was something off with him,” Lisi said.

In mid-November, Lisi told a security guard at Brown University that he saw the man “circling the hallways.” He said the man was consistently hanging around and peeking into room 166 at the building, where the eventual shooting took place. 

Ella Cook and Mukhammad Aziz Umurzokov were both killed in the shooting. Cook, 19, served as the vice president of the Brown University College Republicans.

A law enforcement official walks past articles of clothing on a sidewalk near an entrance to Brown University, Saturday, Dec. 13, 2025, in Providence, R.I., during the investigation of a shooting. (Steven Senne/AP Photo)

Cook was laid to rest in Birmingham, Alabama, on Monday morning.

“I said, ‘Something’s off with this guy, so I gotta say something,’” Lisi recalled thinking when he saw the man on Dec. 1 before going on vacation. “I told my friend, ‘I hope it’s not the guy I’ve been seeing. I hope it’s not.”

The shooting happened inside a classroom in the Barus and Holley engineering building around 4 p.m. Saturday, Dec. 13. Two students were killed, and nine students were wounded.  (Gregory Norman-Diamond)

Lisi said he spoke with Providence Police on Dec. 15.

The custodian claimed that the Barus and Holley engineering and physics building has been “a free-for-all for a long time.”

“Anybody could just come in,” he added.

Fox News Digital reached out to Brown University for comment.