After , Season 10 is finally back. And Season 10, Episode 13's "The Ghost in You"feature a callback to a fan favorite character from five seasons ago.

During a brief clip you see  standing over the grave of Det. Alvin Olinsky (Elias Koteas), who died in Season 5. Read on, below, to remember what exactly happened to him.

“From a creative perspective, it was a decision that evolved organically from the ongoing storyline between Voight and Woods," then-showrunner at the time. "The writers and I kept coming back to this idea that Voight’s decision to kill Bingham should cost him something.

Over time, we landed on the notion that Olinsky should be the person to pay for Voight’s sin because Voight admired and loved him so much.”

Eid continued, "From a business perspective, however, this was an extremely difficult decision. Elias is a terrific actor and a good person. He’s also been an important part of the show since the very beginning. So this part of the process was really challenging. But Elias handled the news like a true professional and remained committed to the show and his character until the final shot. We will miss him dearly.”

Watch on NBC Wednesdays at 10/9c and next day on