Not episodes but Podcasts:
Hunting Warhead: Follows a journalist and police on a global mission to expose the darkest corners of the internet.
https://www.cbc.ca/listen/cbc-podcasts/387-hunting-warhead
Death in ice valley: Podcast investigating a mystery about a dead women in Norway unsolved for almost half a century.
https://www.bbc.co.uk/programmes/w13xttp4
The Outlaw Ocean: A seven-part series that explores a gritty and lawless realm rarely seen, populated by traffickers and smugglers, pirates etc.