Voight takes a murder case personal after his own son, Justin, becomes involved. Voight will find himself forgetting justice and the law as he becomes consumed with revenge in the season finale of "Chicago PD" airing this Wednesday night.

The upcoming episode titled "Start Digging" starts when the team discovers the body of a woman stuffed in the trunk of her car. As the team investigates the case, they discover that the victim is Melissa Wilds, a widowed single mother who was in constant contact with Justin.

Soon after, Voight and Lindsay find Justin attacked and disposed of in the same manor. He is rushed to Chicago Med. Thankfully, Justin is still alive but is in critical condition. Voight, who has just been recently reunited with his son, is deeply affected by the attack.

In the first exclusive sneak peek into the upcoming episode, Voight arrives at the precinct with $90,000 in cash. He tells his team to contact all their CIs and whoever can provide information will earn the cash reward. Voight also requests for the team's commitment to the case. He tells them that he will do whatever it takes to find the culprit and advises that anyone on the team not comfortable with his methods should take a few days off.

Voight begins the investigation and finds himself using tactics considered outside the boundaries of the law — these are also the very same tactics that landed him in jail. Lindsay does her best to remind Voight that he has a grandson now and hopefully, it prevents him from doing anything illegal.

In the second sneak peek for "Start Digging," the team discovers that Melissa and Justin may have been mutual targets due to their connection to each other. They discover that Melissa used her real estate career to leak private information that would be used for home invasions.

Ruzek points out that Melissa could not have orchestrated these robberies alone and was likely to have had help. He points out the possibility that Justin may have been involved. This deeply upsets Voight because he believed that his son has truly changed. He retreats to his office and is comforted by friend Koteas. Voight explains that he hoped Justin would have asked for his help if he was in trouble. Koteas assures him that he is on Voight's side and that finding the culprit is all that matters in the end.

To see the thrilling resolution of "Chicago PD," don't forget to catch "Start Digging" airing May 25, Wednesday at 10 p.m. ET on NBC.