Spoilers for Deus Ex: Mankind Divided - A Criminal Past follow!
As a Junkyard member in the Pent House, Wilburg oversaw Junkyard's operations in harvesting augmentations from inmates executed at the prison. At some point, Wilburg got into a dispute with Oscar Mejia (Hector Guerrero), a fellow Junkyard member and undercover agent working for Interpol. Wilburg threatened to have Guerrero removed from Junkyard, meaning that he would lose everything he had worked for in the past two years. Wanting to protect his position in the organization, Guerrero broke into Automated Security and hacked a sentry bot, programming it to target and kill Wilburg.
After his death, Wilburg's body was taken to the infirmary where Peter Wörthmüller harvested its augmentations. By the time Adam Jensen arrives there, the autopsy is still in progress, but Wilburg's heart is missing from his chest cavity. An augmented heart, which is presumably his, can be found in the tunnel leading from the infirmary to solitary confinement.
Wilburg seems to have been well-respected by his fellow inmates. Several inmates in cell block A will tell Jensen that when they first arrived in the Pent House, Wilburg took care of them and helped them adjust. Frederick Flossy seemingly also holds him in high regard. When Jensen meets him in the yard, Flossy will tell him that Wilburg "was the king for a lot of folks in here" and that he suspects Stenger, the Pent House's head of security, is behind him getting killed.