charlie tan was an ivy leaguer with a bright future. but then, charlie's dad was killed in the tan home and everything changed. police areer being told one sto but the evidence was telling them another. and t there were three 911 call. did one of them hold the clue that would unlock what really happened onat that wintry night? here's dennisy murphy with "hoe of secrets." >> reporter: cayuga. that's cayuga lake in ithaca, new york. it's where you'll find one of the most prestigious universities in the nation. cornell, the ivy league, big red. more than 13,000 undergrads here working towards degrees will with good fortune take their places in medicine, the law, the arts. there's no doubt a cornell education can be a gold-plated entrance ticket to adult life. and only the best need apply, students like charlie tan. he was so kind, his classmate featured him in a video, random acts of kindness. giving gifts to complete strangers. >> not just a great kid but the greatest of great kids. >> charlie was the son of chinese immigrants who became "