More often than we’d like to believe, people get away with murder. In cold cases, cops have retired. Witnesses have died. Evidence has disappeared.

Unsolved: A murder mystery podcast is a true crime podcast series powered by investigative journalism from USA TODAY and the Milwaukee Journal Sentinel, guides listeners through these real-life cases, uncovering new clues along the way. The series features new unsolved cases and true crime cases each season.

Season four of Unsolved: A murder mystery podcast delves into the disappearance of Alexis Patterson, a 7-year-old girl who disappeared on her way to school in 2002. At first, there was a massive search and sympathy for her family, but that quickly changed as her parents became suspects. Over the years, there have been conspiracy theories and false leads and cases of mistaken identity. Still, her mom has never given up hope that Alexis will come home again someday.

Season three of Unsolved: A murder mystery podcast tells the story of Father Alfred Kunz, whose throat was slit inside St. Michael School in 1998. Some believe his death was linked to his battles against evil. Others believe his all-too-human flaws were to blame.

Season two of Unsolved: A murder mystery podcast, released in 2017, examines the case of toddler Michelle Manders, who vanished from her bedroom in the middle of the night in 1981. Did she wander alone into the darkness? Or was she kidnapped?

Season one of Unsolved: A murder mystery podcast, released in 2015, explores the circumstances surrounding the death of 14-year-old John Zera, who disappeared from Franklin High School in 1976. The seven episodes follow investigators through decades of dead ends as they hold on to hope of finding the killer. For more information on the series, visit http://usatoday.com/unsolved.

For more reporting on cold cases, unsolved cases and true crime detectives, as well as additional true crime stories and investigative journalism, visit witness.usatoday.com. Crime reporter and investigative reporter Gina Barton is also host of Untested: A true crime podcast. Subscribe here for the story of how Annie Harrison joined the ranks of true crime detectives and hunted a possible serial rapist.