Ok, let's put our noggins together!
His apartment door was found unlocked with his keys inside, and his car was parked there.. So the theory that he got lost after he left the club and didn't make it home doesn't seem to be a possibility.
His phone last pinged around the time he left the club at 12:53, right? Maybe the battery ran down? Maybe that's one of the reasons he left? He was probably on it a lot that night. That Instagram post was posted from Syntax - the last place he was seen.
It seems like he made it home. But did he attempt to go back out again? Did someone follow him? We haven't heard about what the apartment looked like inside, have we? Any signs of struggle, any signs of a crime being committed? Was someone waiting for him to get home and they confronted him? I'm wondering what the apartments look like. Did neighbors hear anything? SOMETHING IS NOT ADDING UP!
What are your theories, sleuthers??
On the question of pinging. Here's a rough idea of how it works:
When you turn your phone on it pings the nearest tower with the strongest signal telling the network "Hey, I'm here, I'm online and ready to rock n roll."
When you place a call or send a text message or you receive a call or text then your phone will ping the nearest tower with best signal again, if you are talking on the phone for any length of time the phone will ping out every few minutes or so to make sure it has the strongest connection.
When you use data the same thing happens, when you first go onto the internet your phone will ping for the best signal and it will repeatedly ping every few minutes to maintain the strongest signal.
Now, lets say you're not using your phone at all. Lets say you sent or received a text message or phone call and that was it, your phone is now essentially in stand-by, it's waiting to do something. It could take up to 8 hours before your phone will ping a tower again (this time is variable based on carrier, some will send a ping sooner, some even later).
So, with that said. Lets speculate that Adam finished whatever text convo he was having or he shut down whatever app he was using when he left the bar. His phone pinged one last time, if he didn't use his phone again after that ping then the phone would't have sent out another ping for several hours.
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As for a theory.
Since his keys and car were located at his apt I think it's safe to say he made it home from Syntax. It wouldn't make sense for him to drive home from Charlies, park, go into his apt just to leave his keys behind and then walk to Syntax. I would never leave my keys behind at my home and leave an unlocked door just to walk a half mile to a bar, I don't think anyone would do that, esp not in a city. No, I think he made it home from Syntax, put his keys down and maybe decided to step outside for whatever reason.
If he was getting on gay dating apps I don't think they had anything to do with him disappearing. We gay men, esp the younger ones, tend to be quite careful when using the apps because of the threats involved. It's not uncommon, esp in larger cities, for homophobes or gang members to pose on those apps for the purposes of meeting up with a guy to assault him and rob him. Also, using a bit of social profiling, Adam doesn't fit the type that would fall victim to that sort of set-up, in fact I have my doubts that he may have been using those apps for the purposes of cruising. If anything he was seeking out a relationship or friends but not random hook-ups.