Longmire season 4 plot and premiere update: Walter to investigate the murder mystery of Cady's mother?

Longmire season 4 is set to return on Netflix since being cancelled by A&E post the season 3 finale; and fans are eager to know what will happen in the upcoming season.

There are rumours that the season will uncover the mystery behind the murder of Walter Longmire's wife and Cady's mother.

As of now, everyone on the show know that she died of cancer, but the truth behind her death is a well kept secret by the Wyoming county sheriff.

Meanwhile, in a classic Tony Tost move -- he usually tweets lyrics from songs hinting at what will happen in the next episode -- the show's writer shared a series of tweets, with one of them reading as:

"Now playing in the #Longmire writer's room...Tanya Tucker-What's Your Mama's Name?"

Now playing in the #Longmire writer's room: Miranda Lambert - Automatic: https://www.youtube.com/watch?v=2ksWKOy665o&feature=youtu.be

— Tony Tost (@tonytost) January 14, 2015

Now playing in the #Longmire writer's room: Van Morrison - Who Was That Masked Man - original: http://t.co/GTgk6nAHAo — Tony Tost (@tonytost) January 26, 2015

Now playing in the #Longmire writer's room...Tanya Tucker - What's Your Mama's Name: http://t.co/d5jgtbRSOE

— Tony Tost (@tonytost) December 15, 2014

VC Post suspects that Cady may get some clues as to what caused her mother's death and there are chances that she will confront the sheriff, who's her father and could get to know the truth.

The website also suspects that Netflix may release all Longmire episodes at once which is why the whole season will be filmed first.

The filming for Longmire will begin in March, and season 4 episodes are expected to premiere during summer this year.

Robert Taylor and Lou Diamond Phillips will return to the show to reprise their roles of Walter and Henry respectively.