they also found rosser still had keys to the apartments. >> this indicated to us that rosser had likelyto many apartments during his term there as a maintenance worker. >> but jenna's apartment key was not among those found in jeremy's possession. and just like the others, jeremy willingly provided a dna sample. >> my feelings of jeremy was that we might not have our person, being how cooperative he was and his demeanor. >> so investigators had three possibilities. would a dna match be among them? or was the killer still at large? that it's given me time toabout reflect on some of life'seen biggest questions. like, if you could save hundreds on car insurance by making one simple call, why wouldn't you make that call? see, the only thing i can think of is that you can't get any... bars. ah, that's better. it's a beautiful view. i wonder if i can see mt. rushmore from here. geico. fifteen minutes could save you fifteen percent or more on car insurance. >>> with dna samples from three suspects, scientists hope to determine who killed college student jenna verhaalen. and had it not been for

. >> reporter: he brings me in to his home where his younger brothebrobrother rosser he got p net through i can his other brother through the shoulder. he shows me the that ra shrapned says he's not sure if he can ever sit here again. >> translator: i remember everything. everything. may they rest in peace. >> reporter: and who were they, other than his family? his uncle was the local head of islamic jihad, a group that the u.s. considered a terrorist organization. the israeli drone didn't miss, it just fired at him while he was surrounded lie his family. israeli officials say strikes line like the one that killed him are justified because he and allies pose imminent risk. >> hamas is hiding first and foremost behind palestinian citizens and therefore it is responsible for those harms unintentionally. >> translator: i will consider there was someone launching rockets, but what is the fault of chin or the unarmed. none of us were launching rockets. >> reporter: israel will continue to target people who plan rocket strikes. families in gaza will continue to ask why. right now the cycle of v