The acolyte you planted it on escaped to Nocwich. We were able to locate them because the tracker was still functional.

[And Blake, despite the fact that he probably should have been on bedrest, didn't want to leave things unfinished.]

We alerted the authorities to their presence. [What they did after, Viktor doesn't really like, but he can at least know that the acolytes were imprisoned, rather than executed.] Then they returned the tracker to me.