To Play the King : How did John Krajewski know about the rat poison?

How did John Krajewski know about the rat poison?

John (Mattie's journalist friend) tells Sarah on the bus that he thinks Roger O'Neill was killed with rat poison. But how did he work this out? Did he find it out through Mattie? Or did someone else tip him off? If so, who was is? And what are the implications of that?

Re: How did John Krajewski know about the rat poison?

I'd have to go back and watch these again. Offhand, best guess would be that Mattie might have aired some of her suspicions to John, but we aren't shown this, and in one sense it doesn't fit, as Mattie at that point is clearly in love with (or more properly, obsessed by) Urquhart, and probably wouldn't reveal anything to a third party that might cause him to be found out, John especially.

There's a possibility that John's been tipped off by someone, maybe on the coroner's staff. After all, he's a reporter, he'd likely have some sources and know where to dig for dirt. I've always thought it odd that apparently no mention of rat poison traces being found in Roger were in the coroner's report. Maybe a coverup? Or just incompetence? It doesn't seem likely any medical examiner with any experience at all could have missed them--after all, rat poison is a corrosive, so it would seem as if, having inhaled it, there'd be telltale damage around Roger's nostrils or in his nasal passages. But apparently he's just pronounced dead of heart stoppage due to a cocaine OD, and that's that. If Urquhart exercised any influence to keep anything damaging from coming out, we aren't told about it, and it seems unlikely he'd take the risk of doing so in the first place.

Of course, he might not have to anyway--people do buy bad drugs, and even if the poison were found, it could just be chalked up to Roger's having got an adulterated batch from a shady supplier. But it still strikes me as strange that apparently no one so much as ever noticed the substance showing up traces in his corpse.