Aimbot:

https://www.247fairplay.com/CheatDetector/jaco_one lots of Red indicators. especially with shotguns. 

suspicious Headshot accuracy under 100 kills:

870: 80,95%

A91: 84,15% 

DBV12: 52,94%

HAWK: 94,52%

M1040: 93,75%

PP2000: 71,88%

QBS09: 71,43%

Saiga12: 88,75%

SG553: 93,85%

Spas12: 96,63%

together with the fact headshots with shotgun don't do extra damage and most people don't go for the headshots. i think it's save to say this person uses aimbot. unfortunately i can't find any battle reports from this year.