I am sorry but this reads like a hoax story. Was this picked up by a reliable news source?
I'm beginning to question DNAinfo's sources as well, as they never cite the "business" aspect although the suspect did have a Bitcointalk screen name here.
No mentions of Bitcoin on anywhere except DNAinfo:
http://nypost.com/2015/01/14/roommate-held-captive-kills-gun-toting-lawyer-with-hammer/http://www.amny.com/news/quentin-capobianco-beats-roommate-jesse-smith-to-death-with-a-hammer-in-queens-cops-say-1.9802380http://gothamist.com/2015/01/13/teen_roommate_kills.phpNY Daily News does mention Bitcoins in passing, but looks more like more like a drug related death, than Bitcoin price tanking one.
http://www.nydailynews.com/new-york/nyc-crime/queens-lawyer-roommate-charged-fatal-hammer-beating-article-1.2075743Like the victim had heroine withdrawal symptoms and took it out on the 18 yr old. Like maybe the 18 yr was his "gopher", and the gopher said no to the junkie lawyer finally, and then he turned around and tried to force the 18 yr to sell all his coins and kick him out his pad, then that's when the fight broke out.