pleaded guilty to murdering mackenzie lewis. hought about killing mackenzie, and then he planned the killing of mackenzie, a thoroughly premeditated murder. >> that he knew that he was going to murder mckenzie before she even touched down at the airport -- >> he selected her as his victim, right? >> right. >> was there any explanation at all of what is motivation was to do it? >> none, he never offered any reasoning as to why. or even how. >> aj also pleaded guilty to sexually abusing his first victim. he was sentenced to life without parole. one more thing, said the detectives, he was active on the seeking arrangements site right up until he was arrested. >> even after we made contact with him, he was still on that page, still trying to get a date. >> we don't know why, some selfish jerk used his position on a dating website to somehow ensnare this bright, pretty woman, and for what? >> you look at his profile page, he comes across as a gentleman, somebody that he truly is not. that is the whole cautionary tale is that you never