At the center of the investigation into Sheryl Sheppard's disappearance, there is a gaping hole: missing information from one of the key figures in the case, Sheryl's fiancé Michael Lavoie.

Lavoie has not participated in any of the official searches for Sheryl and has spoken with investigators for less than 30 minutes over the past 19 years.

In an attempt to collect the missing information, David Ridgen looks for people who knew Michael intimately.

First, we hear from JP, an anonymous witness who shares details of Michael's childhood and his criminal past.

Michael's eldest brother Steven Lavoie declined to be interviewed for this series, but Steven's wife does share her memories of Sheryl and her own theories about what may have happened in January 1998.

She also connects David with Michael and Steven's mother, Pat.

Pat reminisces on the nightmare that followed Sheryl Sheppard's disappearance for the Lavoie family: the unwanted media attention and the internal family divide it caused.

Pat also reflects on the New Year's Eve proposal and the timeline of the events the weekend Sheryl went missing.

Pieces of the story come together as David continues to speak with people in Sheryl and Michael's sphere in the ongoing investigation of the case.

WEB EXTRA:

Keep track of who's who in Season 2 of Someone Knows Something.