Here's a larger snapshot of the first incriminating post, translated via Google Translate. (Untranslated image is at the end)
You can see that he claims a AH-26 was shot down at 17:50 (5:50 PM) MSK aka Moscow Standard Time. which would be around 9:50 AM EST aka Eastern Standard Time.
The reports that a Malaysian commercial plane "crashed" near the Russian border was first posted on FR at 11:25 AM EST, just one hour and a half later.
The Google Cached webpage of the incriminating post also has a timestamp showing it was archived on 17 July 2014 16:10:43 GMT,
16:10:43 GMT aka 4:11 PM GMT, which is 11:11 AM EST, just 20 minutes before reports of a crashed plane started circulating.
ITAR-TASS, RIA Novoski and Life News, all Russian propaganda outlets, reported that an AN-26 was downed by the rebels an hour before the truth came out.
All quoted "eyewitnesses" and the rebels themselves as admitting to it, and posted photos and videos of it a full hour before up to an hour after a commercial plane was reported to have "crashed", via their own websites and social media posts which I have linked to.
RIA Novoski reported an AN-26 shot down by separatists at 18:13 Moscow Time July 17. (translated from Russian)
Life News reported an AN-26 shot down by separatists at 18:34 Moscow Time July 17. (translated from Russian)
ITAR-TASS reported an AN-26 shot down by separatists at 20:01 Moscow Time July 17.(first English-language Russian source reporting this).
You can check for yourselves, and then realize that reports of the missing airliner surfaced about an hour afterwards at 11:30 EST aka 19:30 Moscow Time that a plane had "crashed" in Eastern Ukraine. Of course, the Russians are probably going to delete those reports soon once they get their bearings on this catastrophe.
As I said earlier it is most likely that the rebels did it.