My point is, again, that a mere failure to report is not a enough, but some kind of affirmative act is required to make it a crime. For example, for a prosecution under 18 USCA 4, misprision: “Affirmative step to conceal is required element of misprision of felony; mere failure to make known does not suffice.” (U.S. v. Warters (5th Cir. 1989) 885 F.2d 1266). “An essential element of the offense of misprision of felony is concealment, and mere failure to report a felony is not sufficient to constitute a violation under this section.” (U.S. v. Johnson (5th Cir. 1977) 546 F.2d 1225.) See also Lancey v. U. S. (9th Cir. 1966) 356 F.2d 407 [“positive act” required]; In re Morris (Ariz. 1990) 793 P.2d 544 ["The elements of the crime of misprision of felony have been stated to be: (1) a felony was committed, (2) defendant had knowledge of the felony, (3) defendant failed to notify authorities and (4) defendant took an affirmative step to conceal the crime.... Mere passive failure to report a felony has been held insufficient to sustain a conviction.").
Same thing with being an accessory, e.g. “Mere knowledge of a crime and a failure to report the same do not alone constitute being an accessory.” (People v. Broom (Colo.App. 1990) 797 P.2d 754.) “Just as a defendant's mere presence does not establish his intent to participate or assist in the crime, neither do any of the other factors, such as failure to assist, flight, or failure to report the crime. There must be something more, some affirmative act by the defendant by which he evidences an intent to facilitate the crime.” (Brumley v. DeTella (7th Cir. 1996) 86 F.3d 856.)
Even your newspaper articles (again, no case law), which are notorious for getting the law wrong, speak of “taking affirmative steps.” Turtlemania’s question involves a mere failure to report, not taking any kind of affirmative steps to conceal. So the answer is, NO, if Jane merely knows that John committed a crime and does not report it, she has not committed any crime (unless, as IAAL points out, Jane is a member of a class of professionals required to report). If Jane helps John conceal the crime, then she has committed a crime herself.