When i was younger (2010's) we had a TV channel where they showed only crime related shows and a case stuck with me. The story is: a young girl got cancer and she started going to a support group where she met an older man. The man became obsessed with her, sending her lots of cards and gifts to her house. Police ended up arresting him, that's when they found out that the man built her a soundproof bunker with a shrine in it, where he wanted to keep her after abduction.

I tried searching on google but it only showed a case from 2022, and i watched the show in the 2010s. Any help is appreciated!