The plot of "Longmire's" fourth season may be tackling the long-running mystery that the series never dealt with when it was still airing on A&E – the death of Cady's mother. 

Fans of the revived crime drama know that, in the first season of the show, Walt Longmire (Robert Taylor) was aware that his wife was murdered. However, the identity of the killer was never revealed. His daughter Cady (Cassidy Freeman) believed that her mom died because of cancer, but she later on discovered that her father had been hiding the truth from her.  Venture Capital Post speculates that in the upcoming season, the mystery of Mrs. Longmire's death may be solved. 

The speculations began when the series' head writer Tony Tost posted a series of cryptic messages in his Twitter account. Tost is known for posting the music that he plays while writing episodes for the show.

One of his tweets reads, "Now playing in the #Longmire writer's room...Tanya Tucker - What's Your Mama's Name: http://youtu.be/fnJHc6CkggA." 

This tweet could be a reference to Cady's mother, whose death paved the way for Longmire's return to law enforcement. However, Tost neither confirmed nor denied the current plot rumors for the upcoming season of the Western-inspired crime series. 

"Longmire" had a successful three-season run in A&E before the cable network cancelled the show in August last year. According to reports, the show's fanbase is composed of matured audiences, which is not the age bracket that the network is trying to attract. 

Fans expressed their disappointment on Twitter after the show's cancellation was announced, making a record breaking petition to renew the show using various social networks. In November, online streaming site Netflix announced that they will pick up the show's fourth season.

The production for "Longmire" season four will start rolling in March, and the premiere episode is scheduled to air this summer.