On Quantico Season 3 Episode 13, Alex and the team stake out Eamon's funeral, expecting the police to arrest Devlin on sight. Instead, the police let him walk straight inside and deliver a eulogy where he promises to forgive past grievances and give up vendettas.
The team realizes that one of Devlin's men, Bobby, was loyal more to Eamon, and so they take him, and he gives up Andrea and Isabella's location. When the team gets there, they manage to save Andrea, but Devlin grabs Isabella.
Devlin reiterates the terms. Give him Ryan Booth, and he will release Isabella. The plan is to kill Devlin and grab Isabella, but things don't work out that way. Devlin kills Andrea when he runs to plead for his daughter's life.
Ryan surrenders to Devlin, and Isabella is freed. Devlin beats the life out of Ryan, but Ryan manages to clue the team to where he's being held. When everyone arrives, Devlin is gone, and Ryan barely has a pulse.
In the end, the team manages to catch up with Devlin. Instead of bringing him to justice, they let Bobby murder him. Ryan still hasn't woken up yet. Jocelyn and Owen kiss, suggesting that they will start dating. Alex asks Isabella if she wants to come back to America with her.