International criminal Chant confronts a diabolical doctor in this action-packed thriller from the author of the Mongo Mysteries.   When John "Chant" Sinclair learns his oldest and closest friend has been murdered, there's only one thing on the professional killer's mind: revenge. But the man who inflicted Harry Gray's slow, painful death is no simple thug.   After being thrown out of medical school, Richard Krowl dedicated himself to becoming a highly trained specialist in the art of torture. Now, other sadists attend his seminars, learning the tools of the trade from a "doctor" whose horrifying skills know no bounds.   To avenge his friend, Chant must travel to a remote Pacific island and infiltrate Krowl's secret facility. What awaits him is more terrifying than most could imagine, but Chant has seen the depths to which humanity can sink--and nothing will stop him from exacting justice by any means necessary.   Silent Killer is the 2nd book in the Chant Mysteries, but you may enjoy reading the series in any order.