In Squid Games, we see the policeman visit his brothers dorm room to find the business card with strange symbols. This leads the policeman to believe that his brother is a participant in the current Squid Games. But in the end we find out that his brother was missing for multiple years, rather than just a couple of weeks as implied by earlier episodes.
So why would the policeman's brother keep a dorm room after all these years? If it was for cover, why did he stop paying for it all of a sudden (the landlord lady mentions she'll clear it out soon for non-payment)?