(a) For purposes of applying AS 12.10 governing limitations of actions, in a prosecution under AS 11.31.120, the statute of limitations begins to run
(1) when all the crimes that are serious felony offenses that are its objects are completed;
(2) if all the crimes that are its objects are not completed, when the last overt act in furtherance of the conspiracy is done by the defendant or any of the other coconspirators; or
(3) when the defendant informs law enforcement authorities of the existence of the conspiracy and of the defendant's participation in it.
(b) In this section, “overt act in furtherance of the conspiracy” has the meaning given in AS 11.31.120.