He is located in the Union Security safehouse in Newtown on the first floor and is armed with a G17handgun. When players first encounter him, he tells them to meet up with Todd Stephens, who asks them to find Richards, another member of Union Security. Later, when the player completes the quest, Tyrel will congratulate the player for finding the key and remarks that the remaining Union Security members can finally head to the Stadium.
Interestingly, even though Todd Stephens says they are defenseless, Tyrel Johnson is armed with a G17.
That said, it could be surmised that the surviving Union Security officers at least have pistols as a mean of self-defense, yet are unwilling to venture out to look for Richards due to the lack of firepower or ammunition. Instead, they choose to request for the player's help finding Richards, because the players should have obtained better weapons by then.
There is a possibility that Tyrel is Shenice Johnson's husband or relative, since they both have the same surname.