... ... .....Christopher was killed by Tony in the episode "Kennedy and Heidi". The two were injured in a severe car accident while driving back from a meeting with Phil Leotardo and the New York crew. The song he listens to before the accident is Pink Floyd's "Comfortably Numb", performed live by Roger Waters and Van Morrison. The song makes references to drug abuse, as Christopher has a substance abuse problem himself. Christopher lost control of his sports utility vehicle, nearly side-swiped an oncoming car, ran off the road, and rolled several times before coming to a stop in a ditch. Christopher was not wearing a seat belt and the crash led to severe internal injuries, as evidenced by the blood he was coughing up. Christopher then pleaded with Tony to help him avoid getting in trouble for driving under the influence, mumbling about drug tests. Tony stumbled out of the car to help Chris after noticing that a branch had impaled the baby seat in the back where Chris' daughter could have been sitting. Chris' ongoing irresponsibility and increasing fears that he would turn State's witness infuriated Tony, leading him to make an impulsive executive decision. Instead of calling for help, Tony suffocated his nephew by pinching his nostrils shut, leading Christopher to choke to death on his own blood. Throughout the remainder of the episode, Tony displayed the proper decorum for the family in mourning, yet could barely restrain his jubilation that he was finally free of the burden Christopher had placed upon him for so long.

Above from Wikipedia -- http://en.wikipedia.org/wiki/Christopher_Moltisanti

You should Google The Sopranos -- lots of web sites about all the episodes and characters.

Another good place to ask anything is:
http://us.imdb.com/title/tt0141842/board/threads/

Robt.