Extinction

This book by Douglas Preston takes place in an exclusive private enclave deep in the Colorado mountains, where scientists are working to bring back to life extinct species such as mammoths and sloths. Only the uber-rich can afford to vacation there and watch the animals come down to the lake at feeding time. Then a young couple of newlyweds is savagely killed on an overnight outing, but their bodies have disappeared. 

Booklist summarizes, saying that the book has "echoes of Michael Crichton's Jurassic Park. In a resort park, extinct animals are brought back to life using cutting-edge science, but in no way is this a retread. In fact, for quite a while, it's a murder mystery. A billionaire's son and wife are murdered inside the resort by ecoterrorists, or so it seems. But, as Colorado Bureau of Investigation agent Frances Cash and sheriff James Colcord will discover, there may be other, frighteningly nonhuman forces at work."

Kirkus concludes their review: "The action seldom lets up, and readers will feel the mounting tension and excitement. The setting itself is a scientific wonder, and it must tie into the murders somehow. Meanwhile, Hollywood is filming an action movie in the park, and the pièce de résistance will be the spectacular explosion of a train. But wouldn’t you know, Preston has other plans. Imagine Jurassic Park with the timeline brought forward to the Pleistocene, and you have the Erebus Resort. Science, imagination, storytelling, and action are all here. Fast-moving fun and a highly creative plot."

Publishers Weekly also weighs in with a favorable review: "Preston tweaks the “resurrected species go haywire” trope with a series of ingenious plot twists, and his well-rounded characters make this more than a knowing genre exercise. The results are as smart and spine-chilling as the best of Michael Crichton."