Garrick was a mercenary who specialized in raiding classified and well defended prison facilities and extracting high level prisoners, always using extreme levels of violence. He worked almost exclusively with a unit of highly armed, countryless mercenaries known as the "Wild Bunch". At some point, he successfully raided a CIA blacksite in the Bering Sea to exfiltrate a man named Mahmoud al-Azok. His employer, a Peruvian money launderer paid him to plant evidence that blamed the raid on Peruvian insurgent organization Shining Path. At some point he and Raymond Reddington worked together, though the alliance ended in 2008 when Garrick gave the FBI his train number and itenerary for a stop at Waterloo station in Brussels. Once Red arrived, a hit squad led by Donald Ressler made an attempt on his life, but failed. Red realized that Garrick had betrayed him and shot him, damaging the right side of his face and apparently blinding his right eye. However, Garrick survived and spent 5 years in a prison described as a "black hole". To remind himself of the incident, Garrick never had the facial scarring repaired by surgery.
He organised and led a raid on the FBI blacksite known as the Post Office. The raid began with hijacked garbage truck being driven to the loading bay, and as the truck approached the compactor was opened to reveal armed men inside who quickly killed the FBI guards. Garrick and his men then placed jammers on telecommunications links while killing any guards who tried to stop them. After cornering the remaining FBI personnel in the armoury, his numerically superior force captured them.
The purpose of the attack was to capture Raymond Reddington, but he managed to enter a secure holding cell before Garrick and his men could catch him. After discovering that the cell was reinforced against bullets and explosives Garrick tried to force Harold Cooper to open the cell by threatening to kill him. When this was unsuccessful he dragged Luli Zeng in front of the cell, and threatened to shoot her unless Red opened the door. Red was unable to open the cell, so he shot Luli. He then dragged Dembe Zuma in front of the cell and repeated his demand.
The screen faded to black as a gunshot was heard.
Upon hearing the gunshot, Anslo sends some of his men to investigate.
When they return with Aram Mojtabai and Elizabeth Keen, he realises from Red's reaction that threatening her will probably have a better outcome than threatening Dembe. When he puts the gun to Liz's head Red forces Donald Ressler to reveal the box password. Anslo uses the password and Harold Cooper's hand to open the box.
Anslo and some of his men take Liz and Red to the lower level and begin to drill though the floor. When the drilling is completed they all escape through the storm drains to a waiting ambulance.
In the ambulance Anslo has to drive when Liz's escape causes the death of the original driver. Red's DARPA tracker is removed and taken away by a motorcycle courier, Red is taken to a deserted building for interrogation.
Anslo has Red suspended by his arms and a doctor injects Red with a drug to heighten his sensitivity to pain. Anslo then starts hitting Red, without requiring any information.
After Alan Fitch has finished questioning Red, Anslo asks if he can kill Red. Fitch is initially unsure, but Anslo convinces him to let him kill Red. Anslo approaches Red and taunts Red by saying that after he has killed Red he will go after Liz. Anslo then asks if Red is actually feeling something. As Red plunges the scissors into the back of Anslo's neck he replies "regret".
When the FBI eventually locate the site, the only thing they find is Anslo's body.