On Friday night, NBC "Dateline" viewers will be given an inside look at the Kelsey Berreth murder case investigation. The episode will also include new photos and videos that have not been publicly seen until now. 

Berreth was last seen on Thanksgiving Day 2018 on surveillance footage during a shopping trip with her infant daughter. Following the disappearance of the Colorado mom, police eventually arrested Patrick Frazee for the murder of his former fiancée and mother of his child. Throughout the murder trial, details emerged thanks to testimony from Frazee's one-time girlfriend, Krystal Lee, which led to Frazee's first-degree murder conviction.  

Now, in Friday night's episode of "Dateline," audiences will get a behind-the-scenes look into the investigation as investigators who "cracked the case" are set to speak publicly for the first time. Additionally, family members will also give firsthand accounts of the tragedy. 

A preview of the new episode can be seen below.

The upcoming episode will also discuss someone that had been housed next to Frazee while in jail. According to Jacob Bentley's testimony, and the evidence that he provided, Frazee had allegedly asked him to assist him in killing a number of witnesses in a series of prison notes.

READ: Kelsey Berreth Update: Patrick Frazee's Mistress Says Murderer's Mom Saw Body, Evidence Burned

The new episode of the NBC crime show comes shortly after Lee was sentenced to three years in prison for her part in the murder. During her sentencing, Frazee's former girlfriend said that she was sorry that she "did not save Kelsey," as reported by the ABC-7 Denver. Previously, Lee's best friend, Michelle Stein, had shared with "48 Hours" that her friend had held a "legitimate fear for her life" because of Frazee, which may have prompted her involvement in the crime.

The episode of "Dateline" also follows Frazee's attempts to overturn his prior conviction. On Jan. 6, his court-ordered public defender filed a motion beginning the potentially-lengthy legal process. A status hearing is slated for March 27 in Teller County District Court.

"Dateline" will air Friday at 9 p.m. EST on NBC.