A janitor working at Brown University has claimed that he warned campus security about a suspicious man 'circling the hallways' for weeks before the mass shooting. Derek Lisi said he saw alleged shooter Claudio Neves Valente outside the building which was targeted on December 13 on about 10 occasions from early November. 'He'd been casing that place for weeks,' Lisi told the New York Times on Sunday. 'I knew there was something off with him.' Read more on DailyMail.com 📷 Boston Globe / AFP / US Attorney Massachusetts #brown #brownuniversity #sad #warning #news