A Brown University custodian spotted depraved gunman Claudio Neves Valente pacing school hallways and peering into classrooms nearly a dozen times in the weeks before his mass shooting — and alerted campus security twice about the suspicious figure, a new report said. Derek Lisi, who has worked at the elite school for 15 years, told the Boston Globe he “knew something was off with” the mass shooter before the sicko opened fire in a lecture hall, killing two students, Dec. 13. While Lisi said he twice told the same security guard about a suspicious person lurking around the same building...