He was being investigated by federal officials but he somehow managed to 'put them off the/his scent'.
Scientists are 'on the scent of' a cure. [=are looking for and are close to finding a cure]
The reporter was 'on the scent of' a big story. [=was following/investigating a big story]
(..) Hey, I am not one of your damn animals. Listen, those kids are still alive... but you and I will not be if you continue to scream like that. So, you can pick up their scent, can't you? Track their footprints? I was with the Navy, not the Navajo. So then what should we do? What do you suggest we do? (..)2015 Jurassic World
(..) Let's move it out! This is happening! With or without you. We know that she is in sector five. This is a game we call hide-and-seek. It's a scent drill. We've done it about a thousand times with these animals. When they get on target, and they will get on target... wait to engage. (..)2015 Jurassic World
(..) ...fur as dark night. Eyes glowing red... ...jewels from the pit of hell itself. The giant wolf sniffing... ...savoring the scent of the meal to come. It's not fear that grips him... ...only a heightened sense of things. The cold air in his lungs. (..)2006 300