cap over the gushing well, after 84 days and millions of barrels spilled, as the end of this crisis finally in sight. good evening. i m cynthia mcfadden. we begin tonight with the war on crime. in a new weapon already transforming investigative work. it s called familial dna and it allows investigator to trace suspects through the genetic fingerprints of family members. police in california credit the technology for the arrest last week of a serial killer suspect in a case dating back a quarter century. for now, just two states permit the use of this science. but as david wright reports, that, soon, may change. reporter: he s accused of the most brutal crimes, of molesting and murdering at least ten victims over a 25-year period. but he is now behind bars. because, authorities say, dna evidence ties him to the crime scenes. and for the first time ever in this country, the dna sample that first led police to his doorstep wasn t his, it was his son s. familial dna, it s c