Some of you might recall the earlier adventures of Buglarian FM Borislav Ivanov, who shook up the world in the Zadar Open late last year. His rating was 2227, but his performance rating there was a spectacular 2697. Unsurprisingly, there was plenty of finger-pointing, accusing him of computer cheating; physical evidence was lacking though, so his career has continued unimpeded by any official sanctions.
He has played (at least) three times since then, with dramatically different results. First, he played in the Georgi Tringov Memorial, and he played badly. His rating going into it was 2342, and his TPR a comparatively miserable 1942, a full 400 points lower than his rating and a whopping 755 points lower than his TPR in the Zadar Open. No worries though: in his next event, the Semi-Final of the Bulgarian Championship, he took a strong second place, and the a week or so ago he won a rapid event ahead of many GMs, with a 2696 TPR.
You can read more info here. There's no question that it looks incredibly suspicious, but suspicion is not proof. Bulgarian FM Valeri Lilov has undertaken an analysis of his games from the Bulgarian Championship Semi-Finals (see the last link), and concludes that Ivanov played in three "styles" there: a computer-aided winning style, a computer-aided drawing style, and (just against the one GM he played there) in a natural style (i.e. without a computer's help). Lilov's analysis has a bit of the sharpshooter fallacy to it, but I suspect a Bayesian analysis would still come out suspiciously for Ivanov.
[Paging Mr. IPR to the blog; please call in, Mr. IPR!]