The D.C. Beltway Sniper John Allen Muhammed killed 17 people in Virginia and Maryland (Not D.C. because, ironically, The D.C. Beltway (I-495) has no exit into D.C. proper.). He was first tried in Virginia for which he was convicted of one count of Murder among other charges, for which he was given the Death Penalty. While he was waiting on Death Row for his conviction in VA, neighboring Maryland, which at the time, had a moratorium on new Death Penalty sentences, he was charged with Six Counts of Murder, for which he was convicted on all charges and sentenced to 6 consecutive sentences of Life Imprisonment without possibility of parole.
In addition, his co-conspirator Lee Boyd Malvo (who was not given a capital sentence as he was 17 at time of the crimes) confessed to 14 additional murders the pair committed in California, Arizona, and Texas, and had court cases that were not brought against him in Alabama, Arizona, Louisiana and Washington (state) owing to the unlikelihood of Muhammed ever walking free during his lifetime.
Following the conclusion of his MD trials, Muhammed was remanded to VA where, on November 9, 2009, having exhausted all appeals, Muhammed was executed via lethal injection. Had he somehow had his conviction thrown out in VA, he would have been remanded to Maryland to serve the first of his six Life sentences (As they were consecutive, if he was able to get any one of them vacated, he would still have five more to vacate as well.).
Life sentence means "we will hold you until you die" while death penalty means "we will hold you until you die... and make sure we aren't holding you long." In both cases, the sentence finishes when the convicted is dead, so the one does not normally fight with the other (since they still have to feed, clothe, and give medical attention to them... it saves them money since they don't have to go through the cost of doing it for the natural life.).
