Market Glitch or Manipulation?

It was more than someone mistakenly hitting the B key versus hitting the M key selling off Procter and Gamble.  CNBC quoted Citigroup:

"At this point, we have no evidence that Citi was involved in any erroneous transaction" and the head of the NYSE said "I don't think you are looking for one bank that traded the wrong number of shares."

Other trading anomalies were also emerging: Accenture, a $40 stock, at one point dropped to one cent. ONE CENT. And 3M shares had a wild swing in afternoon trading, falling to around $68, before popping to $90 and finally settling at $84.24. 

Other stocks also inexplicably dropped precipitously to a penny.  Does the word “HACK” possibly enter into this scenario?  A hack with  a motive is either organized crime or “cyber terror.”  What would better cause people to lose trust in the market than this series of oddities being determined to be a hack job – and one for which there is no known cause or fix?  On top of all the other market vulnerabilities, this would appear to be a call to hoard the canned goods and be prepared to sell what exchange investments you have left and look for a spot under the mattress.

To CNBC it sound like “manipulation.”

The SEC is investigating.