. >>> this weeks marks 29 years of frederick cione the only murder of a philadelphia police officer stillolved. greg argos takes a look at the killing on a cold january morning. ♪ . >> reporter: officer cione was a one-year rookie is. >> reporter: 25 years old. working alone january 30th 1970 >> in his patrol car. he gets out to stop three african-american males. >> he approaches the three men. >> in the area of 17th and october ford. >> reporter: it's his last assignment. rookie ambushed shot multi-times >> he go it's down. 47 years later and 26 boxes of homicide files interviews and evidence gathered, officer cione killer never arrested. only unsolved police killing in police department history. >> i have a cold case unit which a lieutenant, a sergeant and about the eight detectives and all they do is deal with cold cases obviously this is one of them >> captain clark runs the huh and knowing a murderer is still free is bothered him for years. >> when one of ours gets killed it's more important for us to try to get it solved >> cracking this is personal >> his brother worked with me man

. >>> this weeks marks 29 years of frederick cione the only murder of a philadelphia police officer stillolved. greg argos takes a look at the killing on a cold january morning. ♪ . >> reporter: officer cione was a one-year rookie is. >> reporter: 25 years old. working alone january 30th 1970 >> in his patrol car. he gets out to stop three african-american males. >> he approaches the three men. >> in the area of 17th and october ford. >> reporter: it's his last assignment. rookie ambushed shot multi-times >> he go it's down. 47 years later and 26 boxes of homicide files interviews and evidence gathered, officer cione killer never arrested. only unsolved police killing in police department history. >> i have a cold case unit which a lieutenant, a sergeant and about the eight detectives and all they do is deal with cold cases obviously this is one of them >> captain clark runs the huh and knowing a murderer is still free is bothered him for years. >> when one of ours gets killed it's more important for us to try to get it solved >> cracking this is personal >> his brother worked with me man