Midnight Museum Mayhem

Riddle: On February 28th in New York Museum, at quarter-past midnight, a security guard named Ollie Bulb is found murdered in the Latin exhibits, along with the "Mythical Crystal Tear of Cepa" missing. Around Ollie are glass shards. Detective Dill is at it again! Detective Dill finds 4 suspects that were in the museum during the murder. Sal Spudder, another security guard says, "I was at the Egyptian exhibits from 9 PM to 1 PM. But Chauncey was at the Latin exhibits at 12:15 PM, though!" Chauncey Chantenay, a scientist studying some artifacts says, "Yes, I was at the Latin exhibit, but I left by 12:20 PM cuz' of the police!" Horace Radische, a security guard visiting on his off day says, "I admit, going here exactly at midnight was a bad choice. Except, the police were already here when I arrived!" Beatrice Lutz, the museum caretaker says, "Gah! That bloody rat! Oh, sorry, I was cleaning the bathrooms between 11:45 PM and 12:25 PM." Upon receiving the autopsy report, it reports that Ollie was killed at 12:10 PM by a glass object. Because she heard every valid witness, Detective Dill immediately knew who it was. Who did Det. Dill suspect and why? And what had happened to the "Mythical Crystal Tear of Cepa"?