Obama team lashes out at Clinton for not disclosing her tax returns:

Releases memo accusing her of “hiding the information,” holds media conference call.

Strategist Axelrod calls Clinton “a habitual non-discloser” and says “the vetting of Hillary Clinton has yet to start.” Listen to call audio here.

Clinton camp hits back: Spokesman Wolfson pens his own memo defending Clinton on openness and calling for more disclosure on Tony Rezko.

Plus: On Clinton media call, strategist Penn insists Obama broke under pressure. “After only a few days of questioning, Sen. Obama’s vote significantly went down.”