Bates Motel season 3 ended with Norman losing his ongoing battle to control his other self, giving in to his serial killer side and murdering Bradley.

Bradley (Nicola Peltz) paid the price for taking Norman away from his mother Norma Bates (Vera Farmiga), but what she didn't realise is that Norman is still carrying "Bad Norma" inside of him.

In an interview during the Banff World Media Festival, Bates Motel showrunner Carlton Cuse teased that after a slow progression into insanity in the first two seasons, Norman is going to show more of his psychopathic tendencies in season 4.

"The promise of Season 4 is Norman unleashed" says showrunner Cartlon Cuse, who developed the series with writer Kerry Ehrin.

"Season 3, the journey was about Norman becoming aware of his pathology, in that he is capable of blacking out and that he does some less desirable things when he blacks out. That's where we start the season. By the end of the season, Norman is moving from one persona to the other without any real cognition of that. And that is the scary evolution. Now that this character is freely jumping in and out of personas, that's going to be really compelling."

Cuse also revealed that the next season will provide a challenge for Norma, the main character's mother, as she deals with Norman's progress into insanity.

"The question is, what can Norma do to save her son as he descends further into his disease. That's really the question of Season 4."

Cuse teased that season 4 is when it will all come to a head.

"When the show started, for Kerry and I, he was just a kid. He was a kid who had blackouts and some issues and stuff. But at the end of the third season of the show, he really becomes unhinged in a different way he had before. That really sets up a different version of the Norman that we know from the movie. The progression of that character now is very exciting. He's going to be driving the story. He's going to be doing some surprising things," the showruner added.

Cuse and fellow showrunner Kerry Ehrin plan to conclude the show in season 5, which means these last two seasons will be building more to the Psycho story.

According to Variety, Bates Motel will be coming back with season 4 and season 5. Both 10-episode seasons will air in 2016.

Executive vice president and general manager of A&E and Lifetime, told Variety, "We are thrilled to bring fans two more seasons to witness the next stages of Norman's transformation into the most notorious psychopath in cinematic history."