The team heads to the factory where the bombs were last pinged and find Damien Darhk and his soldiers in episode 4x01 "Green Arrow".
The team stops a group of Ghosts who are trying to bomb the city's water supply in episode 4x02 "The Candidate".
Oliver and Thea question a group of squatters about Lonnie Machin and Thea breaks one of their arms in episode 4x02 "The Candidate".
Church meets with the various gang leaders from town and takes over as the leader in episode 5x01 "Legacy".
Oliver and the other politicians are held in a disused power plant by Church in episode 5x01 "Legacy".