'Chicago Fire' Season 4 Spoilers: Crew Searches for Casey, Dawson May Be Expecting, New Members Added to Firehouse 51 [Watch]

"Chicago Fire" will see new cast members for Season 4, as the crew continues to look for Casey (Jesse Spencer).

Will Casey and Dawson (Monica Raymund) get back together if he is found? In the Season 3 finale, Dawson took a pregnancy test. Although fans did not see the results, speculation is that she is pregnant since she was in such a rush to tell Casey the news.

But, Casey was missing when she showed up at his apartment. According to The Hollywood Reporter, he was kidnapped. Will he be responsible for the death of the stripper once investigators really dig into the case? Who kidnapped him?

Showrunner Matt Olmstead hinted that Casey will be framed for the murder of the dead stripper, whose body was found at his apartment.

Olmstead also hinted that if Dawson is really pregnant, she would have to be reassigned to a desk job. If the on again, off again couple is expecting, will Dawson lose herself? She loves her role at Firehouse 51 more than anything.

Meanwhile, Entertainment Weekly reports that Fredric Lehne will join the Firehouse 51 crew at the start of Season 4. He will play Deputy District Chief Ray Riddle, who will be the new fire chief above Boden's (Eamonn Walker) new boss.

Riddle is apparently a grumpy guy who is "hard charging" and is working towards becoming Fire Commissioner. Will he get the position?

Reports say that Riddle does not care if Firehouse 51 gets destroyed while he is in the process of climbing all the way to the top. Who will challenge him? And what kind of things will happen to the Firehouse under his leadership?

Steven R. McQueen from "The Vampire Diaries" is also joining the show. He will play Jilly Borelli, who is a new crew member at Firehouse 51 who gets off on a rough start. Will he later blend in with the rest of the crew and become part of their family?

Check out the Season 4 trailer posted to the show's Facebook page where Voight (Jason Beghe) is on the hunt for Casey.

"Chicago Fire" returns to NBC on Tuesday Oct. 13 at 10 p.m.