Took a friend from work who kept his distance and called the police when I was sure it was my bike. I inspected the bike, we chatted a bit about the broken things (tyres and valves were a bit damaged for some reason, and a few more scratches than before), and then I just told him I knew the bike was stolen and that it was mine, that I could prove it with documentation I had on me, that I was going to take the bike back now, and that my friend was currently phoning the police. He seemed disappointed and we had a bit of a chat about his poor life choices, he apologised, and then walked off when he realised I wasn't joking about the police.
Förlåt att jag skriver på engelska. Jag behöver träna mer på svenska :)