a report from the house on coachside lane. >> 91 1, what's the emergency? >> just two weeks before the shooting police records show the wife placed another 911 call. >> yes. hi. my name is jean tan and my husband just beats me up and he need your protection. >> are you hurt? >> yes. he choke me and i'm so scared. please. >> do you want an ambulance? >> no. please come. please come. >> the dispatcher heard what sounded like an ongoing fight between husband and wife. >> hello? >> sorry. >> a deputy was sent to the house and noticed jean tan, the wife, was clearly rattled. reporter john hand of rochester's democr"democrat & chronicle" newspaper. >> they found that jean was still upset. she had some red marks on her neck. but that there wasn't enough there to charge jim tan with a crime. >> so incident over. >> that night. >> he tried to kill me but nothing results in terms of charges or makes it into the paperwork. >> correct. >> so a history of abuse it appeared. if that were the case, charlie had told no one in his circle at cornell university. up on campus,

officers, the wider community certainly knew nothing about the whispers of domestic violence on coachside lane. >> he's a stoic individual, and it's a tough part of his life. >> the record is still sealed, but it's safe to say the tan house was known to authorities. go back to cornell. it's winter of 2015 and charlie is now a sophomore. on a chilly thursday morning he stopped in unexpectedly to visit his football coach. there is a softer side to this coach than drills and xs and os, and his kids know he'll always be there for them. >> our rule is if you have a problem come in and we'll close the door. if you need somebody to talk to, we're here. >> now it was charlie who needed a shoulder or something. >> i said how are you doing. he said good, but he said, i can't make weightlifting on friday. and i said what's problem? he said i got to go home. >> charlie seem ed emotional. clearly something was eating at the student. >> i asked if there was anything he wanted to talk about. he declined. he just said he had to get home. >> it wasn't spring break. classes were in session but charlie got in hi

. >> detective peglow was soon on the way to coachside lane.still had a garbled account from the 911 call. who had shot whom? >> he was trying to protect me. >> your son was trying to protect you? >> yes. >> it looked like what we would call domestic murder. something had just occurred. >> on arrival, the first deputies saw a young man who would turn out to be 19 year old charlie tan standing in the driveway with his mother. >> they were outside the house. it's a safety thing for the deputies. let those people come out. they asked, you know, who else was in the house. >> in the next moments, the deputies heard the son tell a story that sounded like self-defense. he had to shoot, he said, to save his mother. he'd used a shotgun. >> charlie said, my dad's in there. he's dead. i had to do it. he was going to hurt my mom. >> the father is shot because the boy feels his mother's in jeopardy. >> yes. >> it was getting late on a frigid february night. the deputies put the son and mother in the patrol car. >> they asked him where the shotgun was. there