In short it is not Tyler ( some foreign looking in complete black dress , professional using a short sized gun), gun is not AR-15, bullet is not 30-06 etc
The AR-15 is not that long, just over 30 inches from what I could find. Anyway, a possibility would a
bullpup type rifle. About
bullpup weapons, the Wiki begins:
A
bullpup firearm is one with its firing grip located in front of the
breech of the weapon, instead of behind it. This creates a weapon with
a shorter overall length for a given barrel length, and one that is often lighter, more compact, concealable, and more maneuverable than a conventionally configured firearm. Where it is desirable for troops to be issued a more compact weapon, the use of a bullpup configuration allows for barrel length to be retained, thus preserving muzzle velocity, range, and ballistic effectiveness.
For clarification,
breech is described in the Wiki for chamber:
The chamber of a firearm is the cavity at the back end of a breechloading weapon's barrel or cylinder, where the ammunition is inserted before being fired. The rear opening of the chamber is the breech, and is sealed by the breechblock or the bolt.
In other words, the barrel extends behind the trigger when held. For weapons in this class, see the
Wiki list. Rather than going through a list like in the Wiki, looking up reviews, here is one from
AmericanFirearms.org, which shows what such guns, as found on the US market look like with three of three of the top being below 72 cm long.

For some there is information about the length, for others it was necessary to look for it.
Length | 28.15 inches | 32 inch barrel plus 18
See the Wiki. | 26.23 inches | 28.25 |
In the review there were two others, the Israeli
IWI Tavor X95 Bullpup Rifle Bullpup Rifle which is
26 inches long (66 cm), and the
KEL-TEC RFB Bullpup Rifle which is 27.28 inches. Regarding the above evaluation of accuracy, it can not be ruled out that some models can be enhanced for accuracy.
Whatever was seen near the event, the M99 above is quite long, and it is hefty bullet, .416 or .50 (12.2mm) so this can be ruled out. But there was, and this gives an idea of what some snipers can achieve at a distance with the right type of weapon and ammunition.
Its primary market was long-range competitive target shooters and in 2001, a shooter set a world record at 1,000 yd (910 m) with the M99 by shooting a 5-shot group which measured 4.09 in (10.4 cm).
Was a smart bullet used?
If weapon and caliber has to be reconsidered, what about the type of bullet? The Wiki for
smart bullet has:
A smart bullet is a bullet that is able to do something other than simply follow its given trajectory, such as turning, changing speed or sending data. Such a projectile may be fired from a precision-guided firearm capable of programming its behavior. It is a miniaturized type of precision-guided munition.
In 2008 the EXACTO program began under DARPA to develop a "fire and forget" smart sniper rifle system including a guided smart bullet and improved scope. The exact technologies of this smart bullet have yet to be released. EXACTO was test fired in 2014 and 2015 and results showing the bullet alter course to correct its path to its target were released.
In 2012 Sandia National Laboratories announced a self-guided bullet prototype that could track a target illuminated with a laser designator. The bullet is capable of updating its position 30 times a second and hitting targets over a mile away.
In mid-2016, Russia revealed it was developing a similar "smart bullet" weapon designed to hit targets at a distance of up to 10 kilometres (6.2 mi).
If a smart bullet was used it might be able to move straight and then change direction not to go through, but into the body. There are many options. Even if a smart bullet was not used here, it is a trend to keep in mind for the future or maybe consider for the past? Notice in the Wiki that not much has been released for years.