Do we know if the live rounds were ejected from the gun? Was the writing on the casings of the fired rounds, or the unfired rounds? Did he just write messages on three rounds and drop them from his pocket before he left, as a message?
And to link this to the OP… Internet slueths are having a field day declaring the NYPD to be morons because they can see 3 different jackets, 3 different masks, and 2 different backpacks. But if we can see it, so can the investigators. Changing one’s appearance to evade capture is a bog standard movie trope. Is it so hard to believe he really did bring 3 jackets, 3 masks, and 2 jackets? That’s like, not even crazy levels of planning.
Do you have any social media? I also couldn’t find it with a google search, but located it via Instagram. (Note: this requires about 3 clicks to get to; it’s on the 2nd page of the post, and you have to click a link to reveal it)
https://www.instagram.com/p/DDK49I3yWxi/?igsh=MTNkdzF4bTBxZnBvMw==
No Instagram, and you need an account to play video. Bummer.
Ok I finally found it. He does seem fairly frustrated with the gun between the 2nd and 3rd shots, but I’m unable to draw any conclusions from that. The police theory still seems reasonable and I don’t see anything in there that causes me to second guess their conclusions.
Stranger, I see you’ve been typing for the last 10 minutes. Learn some brevity.
First of all, stop mischaracterizing and completely fabricating statements you are attributing to me; nowhere have I said that “the NYPD is a bunch of drooling morons” or even mentioned the police investigation beyond noting that two of the pictures distributed have the suspect wearing different packs. I did highlight the media uncritically repeating some errant comment that someone stated as absolute fact even though it is clearly wrong, and the general lack of basic knowledge that the vast majority of journalists—even those who routinely report in crime and gun issues—have with respect to firearms.
Second, I am not an “internet rando”; I have been a member on this message board for over twenty years and have posted extensively on the technical aspects of firearms as well as my experience as a tactical firearms instructor. Even if you were not aware of this, my previously linked post contains an extensive discussion on why the weapon shown in the video (which despite your complaining of not being available is linked right in that post at the top of the second paragraph) is not a B&T Section SIX-9, a VP9, a Welrod, or any other integrally suppressed manual action pistol. You are free to contest the points made in that post at any length you feel is appropriate but stop mischaracterizing my statements or attacking my character and knowledge without providing arguments of any merit whatsoever.
Third, you can find well established experts on the internet who have also concluded that this was not a Welrod-type gun and is instead just a poorly-set up short action autoloading pistol. For instance, here is Ian McCollum of the Forgotten Weapons Youtube channel (who also created the videos linked in the earlier post demonstrating the functioning of the Welrod and B&T VP9) which came to the same conclusion that I did regarding the claims that this was a Welrod-type weapon or a ‘vet gun’.
When you respond, please come back with something of more substance than calling me an “internet rando” and false insinuations that I have insulted the NYPD or engaging in any other perfidy. Maybe try doing some research and coming back with actual knowledge.
I see you’ve made five posts in one hour attacking my competence, tacitly insulting me, and now telling me how to post. Perhaps you should learn some basic courtesy.
Stranger
[Moderating]
This is veering dangerously close to attacking the post, not the poster.
As is this.
Both of you, cool it.
Obviously you don’t watch our guidebook documentories on modern police tactics, like Law & Order SVU or Chicago PD - or epscially the assorted FBI shows which take it to the extreme, where everything is caught on assorted security cameras and instantly accessed from the local HQ where they manage the manhunt; except when they are busy downloading cellphone data or bank records or assorted private companies’ personnel files. Not to mention that any surveillance footage is useful for a facial recognition match except when the script says it isn’t. (And when they go into cheap hotels or bodegas, the cameras haven’t worked for ages)
No worry - they’ll get the tip they need from a dockworker and/or warehouse employee who’s far too busy to stop loading crates while he talks to the detective.
And who then has a bale of [whatever] mysteriously detach from an overhead crane and land right on him; except leaving enough of him unsquished that the audience can instantly identify him by the clothes he (or rather his body) is wearing.
If anyone else is having trouble finding the video, just go to the Wikipedia article and scroll down to the « Killing » sub-heading.
When they find the perp, the detectives in charge, protected only by a bulletproof vest, will enter the building at the head of the team heavily armoured SWAT.
At least they wear gloves sometimes when inspecting crime scenes nowadays.
Hey, that’s how I was taught to do it by my wise and respected mentor, who (a) never got mentioned before this case and (b) will turn out to be incredibly dirty.
Heck, even the bulletproof vest is optional if the detective in charge has enough plot armor. See every episode of every variant of CSI ever made.
[Moderating]
OK, the cop-show tropes are fun, but this isn’t the right thread for them.
The question of the weapon seems to be answered. It was a 3D printed gun designed to take a Glock 9mm magazine and a 3D printed suppressor.
The question of the weapon seems to be answered. It was a 3D printed gun designed to take a Glock 9mm magazine and a 3D printed suppressor.
And what barrel?
You can purchase Glock-compatible aftermarket barrels online and in some gun stores (and gun shows, of course). They are not a serialized component so they are essentially untraceable unless investigators actually find a purchase trail with a credit card.
Stranger
You continually impress me, is there anything you haven’t done? 
I have yet to perform open heart surgery or assemble an interstellar gravity wave transmitter from common plumbing items, a fan motor, a dumbbell, and a Speak & Spell, but I am told by ads on Youtube that all I need to do is sign up for Brilliant.org and I can learn to do these things after watching a few videos and taking a quiz.
Stranger