Tyrant of the Badlands by Brouwer, Sigmund

Book 4 of The Accidental Detectives, great adventures for reluctant readers! Ricky and his friends are eagerly anticipating their trip to the Alberta Badlands, famous for dinosaur discoveries. But when his friends disappear and Ricky is accosted, it looks as though this dream vacation is turning into a nightmare! Can Ricky figure out who is behind the kidnappings?