Weird neighbor

Although my downstairs neighbor has been the focus of most of my ire, my next door neighbor is not immune.  I don’t see much of him about – he is an older black gentleman who lives alone and who I hardly ever see because he works/is out of his home at strange hours.  Most of what I know is from his car license plates (he has 2 cars!) – which indicate that he is a military veteran, special forces if one of his bumper stickers is anything to go by, and he also has a disabled badge.  One of his cars also has a bike rack – though I’ve never seen bikes on them.  We share a hallway and stairs up to our separate entries – and he has already annoyed me by leaving some junk in the shared hallway for over a month without disposing of it, in addition to repeatedly not latching the front door that leads outdoors behind him, despite my note asking him to do so.  Generally I haven’t been bothered by noise from him, although like last night he does occasionally watch a movie with cranked up bass that I can hear through our shared wall.  But a couple of weird incidences happened recently.  The most recent was that when I got back home on New Year’s Eve, I noticed that the door lock to his apartment had been sealed over with tape saying do not break seal.  I don’t know why – I thought maybe the locks had been changed because he hadn’t paid his rent or something, but he seemed able to break the seal and enter his apartment on New Year’s Day so I have no idea what that was about.  Prior to that, in a period before Christmas, I hadn’t seen one of his cars and hadn’t heard him coming and going from his home for about a month – to the extent that various notes and stuff were piling up outside his door, and there was a bit of a strange smell (although then the hallway got painted and the paint smell overwhelmed all others).  I was a bit concerned about his welfare and did have a look at some of the stuff by his door – there were some notes about overdue bills plus usual stuff about painting and outdoor work updates that I was getting, so I got to a point where I was going to report this to the apartment manager.  But then he did show up again.  It’s all very strange – he seems too old to be still engaged in special forces activity, though I wonder what he might be up to.  Also makes me wonder about the quality of his living situation inside his apartment – I can only judge by his front door, and that doesn’t seem to be in particularly good shape – buckled and presumably very drafty.  I would definitely be cautious to confront him directly should any issue arise, in case he has any war-induced rage issues, so I hope it never comes to that.  Yet another reason I need to move in April.