On this season of Missing Pieces, reporters Grace White and Matt Keyser are investigating the murder case of Sandra Melgar. She's serving 27 years in prison for the brutal murder of her husband, Jaime "Jim" Melgar, the night they celebrated their 32nd wedding anniversary. Why are there so many questions about her guilt?

On this episode: We take a drive to prison to meet Sandra Melgar in her first and only interview since Jim's death. For the past 10 months, Sandra has called the William P. Hobby Unit home, an all-women's prison that sits among the cattle and farmland near Waco. She walked down the hallway with a wooden cane that was too big for her. I was struck by how petite she was. She looked pretty frail, dressed in a white jumpsuit. She had long blonde hair and glasses. She exhaled as she sat down behind the glass.

“They got it wrong, they got it completely wrong, she said."

Listen to the 'Missing Pieces' podcast on iTunes, Google Play, Podbean, and KHOU.com/MissingPieces.

Read more: She's convicted of murdering her husband. Did she do it?

Watch: The murder case against Sandra Melgar

How this story was reported: Reporters Grace White and Matt Keyser spent months reviewing the case file, provided by the Harris County District Attorney’s Office. That was complete with original police reports, investigators’ notes and interrogation tapes, crime scene photos, and Jaime “Jim” Melgar’s autopsy report. White and Keyser spoke with prosecutor Colleen Barnett, who provided great detail about the state’s case against Sandra, and family members of Jim and Sandra, who provided valuable insight into their life and marriage.

If you have any questions or information about the case, email Grace and Matt.

Photos: Behind the scenes of 'Missing Pieces' Season 2