Invisible Prey

In the richest neighbourhood of Minneapolis, two elderly women lie murdered in their home, beaten to death with a metal pipe; the rooms ransacked, only small items stolen. It's clearly a random break-in by someone looking for money to buy drugs.
But as he looks more closely, Lucas Davenport begins to wonder if the items are actually so small or the victims so random; if there might not be some invisible agenda at work here.
Gradually a pattern begins to emerge. But the clues that connect a seemingly random series of murders will lead Davenport to somewhere he never expected. Which is unfortunate, because the killers - and there is more than one of them - are expecting him...