murder of an 11-year-old girl, years later, what was it that broke this wide open? here s abc s marci gonzalez. reporter: the agonizing, nearly 46-year-long manhunt for this little girl s killer, finally over tonight, according to police. generations of investigators worked on her case. we never gave up. reporter: linda ann o keefe vanished in july of 1973, while walking home from school. the 11-year-old found the next day strangled in a ditch. newport beach police retelling the details of that day from her perspective last year on twitter, and putting out this dna-generated composite, hoping to spark new leads. but it was a recent dna match on the genealogy website family tree dna that police say led to their suspect, james alan neal. they were able to get additional dna, which resulted in the corroboration of the dna from the victim s body. reporter: it is the same technology used to track down the golden state killer, and now, police calling this cold case closed, arrest