Aceveda works with the Justice Department to bring Detective Terry Crowley onto the Strike Team to try to gain evidence to use on Vic.
As Vic and Aceveda struggle to stay one step ahead, their tactics draw the ire of Claudette, who is determined to arrest Armadillo after he rapes a young girl.
Separately, Vic hires a private investigator to search for Corrine and the children, and discovers her seemingly preparing to file for divorce.
He moves out of his home and preemptively files first in an attempt to gain a better chance of retaining his parenting rights, but this only serves to widen the distance between him and Corrine.
The Strike Team privately plans to rob the money train, knowing that they would be financially secure for a long time should they succeed.
[5] In the aftermath of the money train heist, the Strike Team resolves to lie low and avoid any controversy but quickly find themselves marginalized and lacking vital information.
When some of the money from the heist is revealed to be marked for a federal case, the Team struggles to stay ahead of Dutch, who begins to suspect Vic.
However, a defense attorney is killed, and the ensuing investigation leads Claudette and Dutch to discover that the victim had been a heavy drug user for the past three years.
[6] Monica Rawling (Glenn Close) takes over the role as Farmington's new captain, and implements federal asset forfeiture laws to seize any property tied to drug dealing, using the money to fund the department and give back to the community.
The pair enter into a dangerous situation when trying to control major drug lord Antwon Mitchell (Anthony Anderson), who blackmails them and coerces Shane into accepting an order to kill Vic.
[7][8] Internal Affairs Division Lieutenant Jon Kavanaugh (Forest Whitaker) begins an investigation into Vic and the Strike Team.
Applying pressure to the team in any way he can, Kavanaugh finds out about Mackey's share of the money train haul after interrogating Corrine.
Kavanaugh freezes the Strike Team's assets but Vic manages to secure bail money for Lem and assists in providing safe passage for him to leave the country.
Kavanaugh orders Aceveda to lie to Vic and say that Lem had revealed the Strike Team's involvement in the robbery of the Armenian money train.
Steve Billings functions as the interim "jellyfish yes-man" Captain of the Barn while Danny deals with pregnancy and refuses to divulge the baby's father, who is eventually revealed to be Vic.
Kavanaugh, convinced that Vic killed Lem and desperate to close his case after being given a 24-hour turnaround deadline by the Assistant Chief, resorts to planting evidence and coercing witnesses to lie about the Strike Team.
Shane's subsequent behavior arouses suspicion in Vic and Ronnie, and after reviewing a report by Kavanaugh of the night Lem was killed, they both realize the truth.
However, Shane takes steps to rectify this mistake, kidnapping Corrine and Vic's daughter Cassidy before ambushing and severely wounding the Armenian hitman sent to kill them.
Claudette makes strong efforts to solve a brutal mass murder after learning the Barn could be shut down if no improvements are made by the time quarterly crime statistics are released.
Shane, despite holding his written confession as leverage over Vic and Ronnie, agrees to help stop the Armenian threat in order to protect his own family.
Shane escapes and, after realizing that his partners set him up to die, blackmails a pimp from a previous investigation to help him perform simultaneous hits on Vic and Ronnie.
Dutch and Claudette begin a full-scale investigation into Vic and Ronnie in a final attempt to take down the remaining Strike Team members once and for all.
After a failed attempt to incriminate Vic in the act of aiding and abetting Shane, Dutch fakes the arrest of Corrine in order to preserve her cover.
Vic and Ronnie lead the cartel and the leadership of the black gangs into an ICE trap, which Aceveda uses as a publicity stunt for his mayoral campaign.
Realizing that Claudette is watching his reaction in the security monitor room, Vic stares into the camera before ripping it out of the wall in a rage.
After hearing police sirens, he rushes to the window and stares out at the street below before returning to his desk, removing his gun from a lockbox, and leaving.