Murder in the Dark by Simon R. Green
If you haven't yet discovered Simon R. Green's Ishmael Jones mysteries, Murder in the Dark is a good place to start. It's not quite as graphically violent as some of the earlier ones in the series. In fact, this one is reminiscent of Agatha Christie's And Then There Were None with the addition of Green's trademark black humor. In 1963, Ishmael Jones crashed to Earth in an alien space ship. Now, he lives in England in human form and works as a field agent for the mysterious Organization, investigating weird and unusual cases. There are more than you would expect in an ancient country with a history packed with "monsters and mysteries". The latest mystery involves a mysterious hole in the side of Brassknockers Hill near Bath. Ishmael and his partner, Penny Belcourt, are dispatched with an urgent assignment to protect the scientists now working at the site. An archaeologist working at a dig fell into the hole and disappeared. Ishmael and Penny find an odd ...