This is the 12516th most frequent Turkish word.
hırsızının
"Hırsızının" means "of the thief" or "the thief's" in English.
In this sentence, 'hırsızının' determines possession (the thief's hands) and specifies whose hands the belongings were taken from.
Eşyalarını hırsızının elinden aldık.
We took your belongings from the thief's hands.
In this sentence, 'hırsızının' is a genitive form indicating possession, implying 'of the thief' and adding information about whose identity is known.
Hırsızının kim olduğunu biliyorum.
I know who the thief is.
Here, 'hırsızının' again represents possession, relating the trace to the thief and showing who the trace belongs to.