Serial third season of the investigative podcast debuts on 20 September.

Two new episodes will be launched together with the remainder released weekly on Thursdays.

The successful series’ latest run will delve into Cleveland’s criminal court system, a subject the producers settled on after being granted an “unusual” level of access to record inside courtrooms, attorneys’ offices and judges’ chambers.

Sarah Koenig will return with Ohio native Emmanuel Dzotsi. They spent over a year in the city focusing on cases ranging from marijuana possession to felonies.

Koenig said: “Every case Emmanuel and I followed, there came a point where we thought: ‘No, this can’t be how it works’. People who work in the system, or have been through the system, they know this. But millions more people do not. And for the past year I’ve had this urgent feeling of wanting to kind of hold open the courthouse door and wave people inside. Because things are happening — shocking things, fascinating things — in plain sight.”

Serial – a spinoff to radio programme This American Life – shot to fame in 2014 with a series focused on the 2000 conviction of Adnan Syed for the murder of his girlfriend in Baltimore.

The series won a Peabody Award in April 2015 and, according to iTunes, it was the fastest podcast in its history to receive 5 million downloads. Its success even led a judge to grant Syed a retrial.