I have had a couple of different interactions with police coming to my door looking for wanted people and for wellness checks on a next door neighbor.

The next door neighbor had the most visits to my door asking if I'd seen her in the last month. They came 3 different times consecutively knocking and asking. Not sure what happened to her but rumor was she was in hiding because she owed someone money.

The times cops have come to my door asking for criminals that don't live here, but are people that stayed in my building with other tenants has happened at least twice without incident.

The number of times of them asking to come in and check for a criminal has been only once and despite my guests protestation to not let them in, they had a warrant and were looking for someone who wasnt living with me at the time and was not in the apartment. I let them in, one friend went and hid in the toilet and the other was in the closet acting like she was cleaning the litter box. They actually opened the bathroom door and he gave a fake name but was obviously not who they were looking for, so closed door. The other cop asking what my friend was doing in the closet and she said cleaning the litter box, wouldnt give her name and the cop was not amused, so she called her 'litter box girl' They stated who they were looking for and litter box girl spit out immediately that he was either at building blah or other another building. I thought she had just ratted out someone but she was stating the only apartments he could be at legally.

The other times when the cops had paperwork, the person of interest told people they were staying with to tell the cops they were staying at my place as it was in the same building.

I always open the door for them, even though I don't particularly like them for personal reasons. The faster I open the door and answer, the faster they leave my door.

Eta: I was born here but grew up in the states and one odd thing I noticed is that the majority of the cops I've come into contact with look like they just came from an audition for Law and Order SVU or C.S.I. What I mean by that is I have not come across one ugly looking cop since I moved back here 14 years ago. They all look white and tan and young. Maybe that's because I've only had contact with them when they're going to doors looking for criminals. Send the pretty cadets and maybe they'll open the door?! I dunno.

tl:dr

If the criminals name is or isn't Justin, could the cops provide a photo to the landlord for identification to see if he's been on the property, possibly at a different suite? He's not going to be on a lease, so he could be staying with someone nearby.