I'm worried the bike I bought is stolen...

[Abradable Chin]

One thing about conpeople is that they are ultra cool under pressure, so receiving a plausible story, or a receipt might not mean that everything is OK.

I don't think you mentioned where you saw the advert for this bike; perhaps this is for the best. If it was on ebay, then look at the selling history of the vendor to glean information on the frequency of selling bike bits, and the location from photos. If it was on Gumtree, type the mobile phone number in to search for it. Sometimes it will appear in multiple adverts, but the vendor location or name etc will vary.

[thirdcrank]

Forgetting for a moment the "getting the bike back to the true owner" theme and thinking about anything "going wrong" we are really talking about the unlikely event of the police asking questions. One of the key points to prove in handling stolen property is "knowing or believing it to be stolen..." Now, the more there's evidence of concern, the more there's the possibility of things being interpreted as "believing." Fortunately, the other key point is that the property has to be stolen in the first place so no matter how much you believe something to be stolen, you can't "handle" it if it isn't stolen.

[gxaustin]

A friend of mine had a bike stolen from his locked shed. Months later he saw it on Ebay and bought it back cheaply. With advice from an ex policemen he obtained a full chain of evidence which he gave to the police. They were completely disinterested. I'd have thought handling stolen goods might be a goer at least.
My son had his bike stolen from a shopping street outside Aldi by a guy with bolt croppers. The police weren't interested unless HE obtained CCTV evidence. He tried all the shops and local authority because there were some cameras nearby, but they said they'd only give information to the police - and the police were just NOT prepared to get off their backsides.
Moral - whether you tell the plods or not they probably couldn't care less and you might lose the bike without compensation. It will end up in a police auction because they'll never find the owner.
I know another bloke who bought a bike on Ebay after nobody bid the reserve. He made an offer privately and agreed a price. He had to pick it up from 100 miles away but his sister lived nearer so he could pop in to see her on the way. But wait, the seller asked where he lived and it turned out that he was travelling up the M5 in a weeks time. My friend offered to meet him in a services but the guy said 'no worry, you live just off a junction, I'll bring it round'; which he did. Was that bike stolen? It was very new looking and half price. It never occurred to my friend. Nor to me until just now.
Based on the above, I'd forget it and enjoy the bike. The victim was probably insured anyway (like my son was). But be careful next time.

[Tangled Metal]

BTW I got my current and previous bike registered as part of a police drive in bike theft prevention I reckon. A nice discrete stencil with a unique code plus details recorded about the bike and owner. I assumed a searchable database entry would be made that the police know about.

Less than a year later my previous bike got stolen. I recorded all the details including frame number obtained direct from specialized. Shortly after buying the bike I registered the purchase with specialized. Figuring it could be useful say if there was a safety recall our something. Anyway they had the frame number I'd lost.

Anyway it was all in at least 3 online databases for bikes and recorded as stolen. A few days after the theft a.police officer took details of my bike. Unfortunately as a bike nerd I was about halfway through giving a comprehensive description of the bike when she interrupted and told me she had enough information on the bike. I then told her about the police stencil and register along with the number stencilled on my bike. She had know idea about what that register and said it was probably a local thing. She'd contact the local officer to see what it was.

A few weeks later the person who's bike was stolen at the same time told me the police had returned his recovered bike. Anyway I called the officer dealing (in force head office 40 minutes drive away) and he hadn't heard about it.

Anyway I got a new bike and forgot about the stolen bike. On my commute home I spotted the same bike security type of thing going on very close to the previous time. I got it done again but took the time to let them know their own police force has no idea of the security database scheme they're involved in. Told them my bike theft story. The support officer got the real police officers involved in the conversation. They said they'd bring it up with their boss. Doubt they did somehow.

Anyway my conclusion is that if your bike gets stolen you have to be lucky, find it yourself or find someone like the OP with suspicions who's willing to find out for sure whether the bike was stolen then return it to the owner. Any of those options are as likely to happen as the others.

BTW the guy who's bike got nicked with mine had it stolen three times and returned twice. Once by the police and once by a friend who saw a guy riding it which allowed him to get it back through, shall we say strength of personality?!!

[mercalia]

BTW I got my current and previous bike registered . . . . . .

He didnt deserve that luck, such careless ness?

[Tangled Metal]

He lost his bike in the end, but bought a nice mtb later for not a lot of money. Seems second-hand could fund thefts.