Mindhunter has released its second season and it has been summarily devoured by all of its fans who are now wanting more — and rightly so. While the show itself has not yet been renewed for a third season it is likely that that announcement is not long off. With showrunner David Fincher on board (who among other things produced House of Cards for multiple seasons) and with the cast talking about how they have planned for five seasons in total, we probably don't have to worry about early cancellation. That being said, the show is likely to be absent for a while (it took two years to come up with the second season). Fincher is a known perfectionist and it's likely production won't begin until he's 100% satisfied. But that won't stop us from thinking about what we'd like to see in the future. (This list will contain Season 2 spoilers.)
Will They Catch The BTK Killer?
Nearly every episode opens with a vignette of a man credited as ADT Salesman. Viewers have figured out that he is the infamous BTK strangler; Season 2 also mentions him by name. True-crime aficionados know that BTK was not apprehended until 2005 and given the show's setting, it is unlikely an arrest will be made in Season 3. However, BTK had more of a presence in this season, often appearing after the usual cold open slot. It ties into the theme of these crimes having more of an exposure to the public, so while he may not get caught, we will probably see a lot more detail of what he's doing.
More Manson
One of the highlights of this last season was finally getting to see an interview with Charles Manson, thanks mainly to Damon Herriman's performance. However, Manson clearly means a lot more to Holden than just appearing once. Since Season 1, Holden has made it clear he wants to meet Manson and with the latter signing a book for him. it may be that Holden, like he was with Ed Kemper, will be drawn back for another visit. Manson also held a mythic status, compared to other criminals, and it's likely that one interview alone won't be enough to satisfy the FBI.
Bill Tench and his Family
While not based in real life, one of the most upsetting stories this season was watching agent Bill Tench discover that his son was present at the murder of a small child. It took a great toll on Bill, allowed the show to widen the debate on nature v. nurture and finally, left Bill alone, with his wife and child moved away. There are too many unresolved issues here for this to be the end of the story. One possibility is that the next season jumps forward in time a few years and we can re-meet Bill's son as a teenager to see how he's changed (if at all). Either way, this story will have some effect of Bill's character in seasons to come.
Ted Bundy
Rumors abound about which serial killers could make an appearance in the next season. One name that keeps coming is Ted Bundy, who fits for a number of reasons. Firstly, where Season 2 ends (1981), Bundy is already in jail and gained a huge notoriety. Secondly, he has already been mentioned in passing by Bill. And finally, towards the late '80s, Bundy did help the FBI with investigations, most notably the Green River killer. Even if Season 3 doesn't quite get up to this final stage it could at least set Bundy up for a multi-season story arch.
Joseph Paul Franklin
Another possible appearance could be from the white supremacist and serial killer Joseph Paul Franklin. He too fits, historically having been apprehended in 1980. Also, a large part of Season 2 covered the Atlanta child murders and Holden's theory of killers almost never crossing racial lines. The anti-climax of that story is very likely to affect Holden's character, at the very least pushing him to find more answers and new details. Franklin, as a documented racist, proves the exception to the rule and would make a key candidate for Holden's investigations.
Expansion of the Behavioral Science Unit
Season 2 opened with a new FBI Director giving a lot of money and attention to the Behavioral Science Unit. However, other than a glimpse of a new space and the promise of more members of staff, we didn't get to see this expansion. Season 3 is likely to expand on this with numerous new characters introduced and probably furthering the potential for interview scenes now that there will be more people to conduct them. The direction the BSU takes will also be interesting, as this last season sparked a debate about the morality of its actions when BSU member Gregg Smith admitted he leaked information to the FBI execs.
Redemption for Wendy
Wendy had an up-and-down Season 2, mainly ending in her — very reasonably — feeling frustrated. While she finally got to do what she wanted, interview subjects, this was routinely taken away from her by the FBI director. As well as breaking up with her new partner, Wendy was also left on the sidelines while Holden and Bill were working in Atlanta. Whatever she does in Season 3, she certainly deserves to be treated better and here's hoping she gets something of a redemption next time round.
A More Radical Holden?
Holden ended Season 2 on an anti-climax; his theory helped track down a very likely suspect, who was then only convicted for two out of the numerous killings. Holden was brought down by red tape and with a lingering shot of blood on his sleeve, (mirroring a scene from the first episode) it's likely he's feeling guilty for this failure. Also, he clearly has a lot more work to do on his panic attacks. However, all this is mixed in with a huge amount of praise from superiors meaning Holden could be entering Season 3 with an inflated but damaged ego. Next season could see him acting even more radically than he already has.
Robert Hansen
Yet another name being floated for a killer cameo. This one, however, is very interesting, as he was caught in 1983 with the help of the FBI, which could fall under the time period of Season 3. Robert Hansen could be the perfect character for Holden and Bill to redeem themselves, as Holden is an amalgam character sitting between fiction and reality, it would be perfectly fine for the writers to have him help catch the killer. Furthermore, Hansen's murders took place in Alaska, which would be an amazing setting for Mindhunter's beautiful cinematography.
The Killer Across the Table
John Douglas, who wrote the book Mindhunter is based on, released a new book earlier this year, The Killer Across the Table. This could spell interesting news for the show. Just as Hulu bought the rights to Margaret Atwood's (as yet unpublished) Handmaid's Tale sequel, Netflix could purchase Douglas' new book to give them even more material for the series. The book goes into four key aspects of a killer's psychology and could introduce more characters for the show to play with. Potentially it could even introduce new series leads to take over after Holden presumably retires, and bring the show into the modern era, meaning we could come full circle and finally see BTK caught.