If you ever hear me claim that my job is difficult, please do me a favour. Punch me hard on the nose. Writing a weekly opinion column is the easiest job in the world that doesn't involve marrying David Beckham or writing jokes for Marmaduke.

Unlike being an actual reporter – which demands tenacity, extensive fact checking and the ability to remain calm under pressure – my job generally requires just four abilities: 1) the ability to remember what day my deadline is; 2) the ability to set an alarm clock for noon that day; 3) the ability to correctly identify the most controversial technology story of the week; and 4) the ability to decide whose side to take. Actually, even that last one isn't strictly necessary as I'm lucky enough to write for the Guardian. Really, I just have to figure out which side you're on, dear reader, and then pick the opposite just to piss you off.

Or at least that's how it usually works. This week things have gone horribly awry.

It all started on Friday when a story appeared on Techcrunch concerning music recommendation service Last.fm. Back in February, Techcrunch ran a story alleging that Last.fm had passed listening (or "scrobbling") data to the RIAA, the trade body representing American music labels. The story came from an anonymous source close to CBS who, apparently, was subsequently fired (leaving them slightly less close to CBS).

At the time, Last co-founder Richard Jones denied the story in an eloquent blog post entitled "Techcrunch are full of shit". Following the denial, Last.fm fans were quick to attack Techcrunch, with some comparing the site to a tabloid. And yet, as I opined at the time, there was actually fault on both sides.

Certainly, the way Techcrunch wrote the story was reminiscent of a gossip piece. Techcrunch didn't contact Last for comment until after the facts, and the piece was published on a Friday night (UK time) making it difficult for the company to issue a timely denial. For Last's part, even after the weekend, it still took several days to issue a strong statement which came in the form of a blog post. Meanwhile, Last's parent company, CBS, issued the most vague of non-denial denials, which raised more questions than it answered. Everyone ended with egg on their faces and no one really knew the truth.

This time around though, it was a different story. Literally. The new post was written by Techcrunch editor Michael Arrington and contained considerably more detail than the original. After the February story broke and was denied by Last, Techcrunch's Deep Throat offered clarification, claiming that it wasn't Last.fm that had passed on the data to the RIAA at all, but actually CBS that had employed foul means to acquire the data from Last's operations team. When the operations team had found out where the data was heading, claimed the source, the "shit hit the fan" and the transfer was stopped.

For many commentators (including myself) this telling of the story rang much more true, and was certainly far more authoritatively written. Arrington gave more specifics from his source, specifics which he'd taken steps to independently verify.

Even though the follow-up story appeared, again, on a Friday night (for the love of God, Techcrunch) this time Last denied it almost immediately, in a forum post from Systems Architect Russ Garrett. As Garrett noted, though, there wasn't much for Last to deny as "allegedly CBS did the deed". He went on to say that he hoped CBS would soon issue its own statement of innocence.

None of this helped me. As my weekly deadline hurtled closer, I was facing my worst case scenario. On the one hand there was a solid-looking story from Techcrunch and on the other there was a solid denial from a pretty-much vindicated Last.fm. CBS still hadn't confirmed or denied the story. I had absolutely no idea who the bad guy was.

Normally in this situation, I'd just flip a coin to decide who to go after. But not this time. Of all the web 2.0 companies I've encountered, it's fair to say there aren't many I respect more than Last.fm and Techcrunch. I visit both sites several times a day and my admiration for them spans the professional and personal – both companies employ friends of mine and boast employees so dedicated and professional that it almost makes me sick.

There was nothing else for it: if I was going to pick my bad guy, I was going to have to take extreme measures and do something that goes against my every instinct as a columnist. I'd have to get off my lazy arse and do some actual reporting. To make international phone calls to proper sources, using phrases like "off the record" and "deep background". Oh God, I'd probably have to make notes.

But needs must. Feeling slightly giddy, I picked up my phone and started dialing. Three hours later, I put down the red-hot handset and slumped at my desk, exhausted. In front of me were pages of notes – notes which would enable me, for the first and probably last time in this column, to offer you a list of verified facts rather than simply guessing what the truth was. Here goes …

Fact One: Last.fm is innocent.

Let's get this one out of the way straight away. The Techcrunch story makes it clear that, even if there was truth in the accusation that CBS passed data to the RIAA, Last was not complicit. Sources inside Last go further, insisting that at no point did user data leave the London office bound for CBS or the RIAA. As one source put it: "If anyone on our ops team knew about a data transfer to the RIAA, they would have quit. These are super-committed open source wizard supergeeks; neither love nor money would be able to convince them to both keep quiet and stick around." Last also confirmed, in dull technical detail, why it would be impossible for CBS to get that data itself. (Incidentally, the fact that they use phrases like "open source wizard supergeeks" is just one of the many reasons I love the people at Last.fm.)

Fact Two: And yet, there are certainly trust issues between some at Last and some at CBS.

Russ Garrett's initial public denial still left open the possibility that someone at CBS had acted alone, sending data of their own (not obtained from Last) to the RIAA. His hesitation to speak for CBS was probably for good reason. Sources on both sides of the Atlantic agree that while relations between Last and CBS are basically cordial, there are certainly some at CBS who don't have a huge amount of time for the cool web 2.0 kids across the pond. After the February post, a PR representative for CBS in New York issued a flat denial to Techcrunch, but soon afterwards emailed again to ask that it be re-attributed to Last rather than CBS. When the most recent story was published, some at Last theorised that there was "definitely a chance" that a rogue data analyst at CBS could have passed some basic analytics data (which they did have access to) to the RIAA, without Last's knowledge, thinking they were being helpful. Senior staffers at Last were told on Saturday that CBS would be issuing a denial of this on Tuesday – although, curiously, at the same time, some journalists in the US were being told that no such denial was imminent. Other reporters were out and out stonewalled by their contacts at CBS. The CBS denial, when it eventually appeared on Wednesday, came in the form of a one paragraph statement to the Wall Street Journal which ruled out that any user or listener data had ever been passed from CBS to the RIAA and then went on to bitch that "those who consult [blogs like Techcrunch] should be aware of the standard by which such postings are sourced and published". Meow.

Fact Three: Techcrunch is not full of shit. Any more.

Back in February, when the original story was published, by its own admission Techcrunch was going through a difficult period. It felt tired and it made mistakes. Arrington was on holiday in Hawaii after some prick at the DLD conference spat on him. His co-editor, Erick Schonfeld, was in charge in his absence and so was the only senior editor at Techcrunch who saw the story before publication. Unfortunately, he was also the person who wrote it – never a good idea. As I complained at the time, Last wasn't asked for a quote before publication and its denial was buried at the bottom of the post. Since then, though, a lot has changed and Techcrunch is back at the top of its game. The site has made various strategic hires including Business Week's Sarah Lacy and MG Siegler from VentureBeat and the much-boosted team is publishing an average of 25 posts a day, including countless exclusives. Having spoken to Techcrunch staffers it's clear that potentially controversial stories go through an editing process that knocks many other trade blogs into a cocked hat. As a result, big mistakes are few and far between.

Fact Four: Techcrunch made every attempt to verify the story.

Bizarrely – and inexcusably – some rabid Techcrunch commenters have issued death threats over Arrington's coverage of Last.fm. For obvious reasons, running another negative story without checking it out properly first was not high on his list of priorities. Arrington's main source had previously provided multiple tips, all of which had proved to be accurate. And yet Techcrunch still insisted on taking steps to independently verify the new information. After the original story in February, Arrington tried to contact Felix Miller, the CEO and co-founder of Last.fm (you know the Germans make some good stuff), for comment. Miller refused to talk to him. So Arrington tried again, this time through one of Last's investors – a very senior figure in the investment community. Again he was rebuffed by Miller, who palmed him off to CBS PR in New York (Last.fm still doesn't have an in-house PR representative. Which is still ridiculous.)

So.

So what?

After three hours of phone calls and the beginnings of RSI, how much closer did these facts bring me towards choosing who to blame for all of this in my column?

Last.fm was certainly in the clear, but equally it's hard to build a convincing case for blaming Techcrunch. It had a source who had previously proven to be reliable and it had various pieces of secondary evidence pointing to the source being legitimate. Even those inside Last weren't absolutely sure at first that someone at CBS hadn't done anything silly, and CBS couldn't bring itself to issue a denial until five days after the story broke.

Assuming we take CBS's denial at face value – and there's no reason not to – the only remaining possibility is that all three companies have been the victims of a deliberate hoax. A hoax so well executed that it more closely resembles a long con, where the mark (in this case Techcrunch) is given numerous accurate tips before being hit with the sting. What still doesn't make sense, though, is why someone would create such a damaging story out of whole cloth? Did he or she have an axe to grind against CBS – and if so, why try to take down Last too? And if the target was Last, why switch the blame back to CBS? Maybe the grudge was against Techcrunch – Arrington has made his share of enemies and a fake story would certainly seriously damage his credibility. But, again, why make Last and CBS the collateral damage, and where did the previous solid tips come from?

The answer, as I head towards my penultimate paragraph – the one in which a columnist is suppose to tie everything up with a neat conclusion – is that I don't know who's to blame. And neither does Last or Techcrunch. Something is still missing and sources at both companies remain equally baffled at why so much effort would go in to smearing one or other of them. Only one man, or possibly woman, can say for sure what the truth is – Techcrunch's original tipster. And, wouldn't you know, he or she has since vanished off the map, despite Techcrunch offering both anonymity and expensive legal representation.

Until that source reappears, the only sure conclusion I can end with is this: the yelling has to stop on all sides. Everyone needs to stop threatening to cancel their Last.fm accounts or calling for heads to roll at Techcrunch. Seriously – death threats – what the hell is wrong with you? Oh, and Felix, you need to pick up a freaking phone for once in your life and discuss this with Arrington. That's what CEOs do.

There are at least two companies here full of good people, doing a good job. And if either one of them is taken down by this madness, then the real bad guy – whoever he or she eventually turns out to be – will have won.

• Paul Carr is author of Bringing Nothing To The Party: True Confessions Of A New Media Whore. He blogs at paulcarr.com.