Predator Shaefer Trilogy Series by Mark Verheiden, Ron Randall

Beautiful, bold Lt. Ligachev was two months into her first command positionin the Siberian oil fields when her men were slaughtered by an invisible foe. Detective Schaefer has played the Predators' deadly games on the mean streets of New York. Now Ligachev and Schaefer are sent by their governments to winter-ravaged Siberia to eliminate the Predators - if they can keep the Americans and Russians from killing each other first.

Schaefer joined NYPD to "serve and protect." It's a bug in his blood or a chip in his brain. But as bad as things get in the drug-infested concrete jungle there's something worse out there, something that really needs stopping. The last time Schaefer faced it down was three years ago, in Russia. Now he's got another chance to stop that evil. He's heading down to the jungles of South America, and he'll come back with the head of a Predator . . . or he won't come back at all.