This is the 1193rd most frequent Polish word.
śledczych
"Śledczych" means "investigators" in English.
Here, 'śledczych' is used as an adjective-like noun, functioning as a plural noun form meaning 'investigators'.
Pracowałem z grupą śledczych nad rozwiązaniem tej sprawy.
I worked with a group of investigators on solving this case.
In this sentence, 'śledczych' is in the genitive plural form, referring to the investigators.
Wiedza zdobyta przez śledczych była kluczowa.
The knowledge acquired by the investigators was crucial.
Here, 'śledczych' is in the possessive case, denoting ownership of the meeting by the investigators.