. >> reporter: it has been more than three years of pain for barbara quinn's family. >> i still pick up the phone every day to call her. >> reporter: the 67-year-old was killed in april of 2012. prosecutors say coska stabbed coin and stole lottery tickets and bought heroin with the money from cashing them in. >> i have never been more proud of my mother. >> reporter: barbara coin's son found her minutes later. >> she had enough sense to get enough of his dna under her fingernails so he could never harm another family again. >> coska's lawyer told the judge the 40-year-old was addicted to heroin after being prescribed opiates after an injury. will be more out there who are addicted to heroin and have one goal in mind, to steal people's money. >> i know she would have helped you if you would have just asked her. >> reporter: but whatever motivated coska to kill does not matter to her family. >> he does not belong in society. he is far too dangerous to everyone. >> reporter: and coska will be spending the rest of his life in prison without the possibility of parole. in boston, jennifer