Conversation so far:
What are ACORN videos?
In 2009, workers at offices of the Association of Community Organizations for Reform Now (ACORN) were secretly recorded by conservative activists Hannah Giles and James O'Keefe.
What action did James O'Keefe take with the ACORN videos?
O'Keefe selectively edited and manipulated the recordings of ACORN employees, as well as distorted the chronologies. Several journalists and media outlets have expressed regret for not properly vetting his work.
Did O'Keefe get in trouble for manipulating the recording of ACORN employees and distorting the chronologies of the ACORN videos?
On March 5, 2013, O'Keefe agreed to pay $100,000 to former California ACORN employee Juan Carlos Vera for deliberately misrepresenting Mr. Vera's actions.
What else interestesting happened during the recording of the ACORN videos besides James O'Keefe agreeing to pay $100,000 to Juan Carlos Vera?
The California Attorney General's Office granted O'Keefe and Giles limited immunity from prosecution in exchange for providing the full, unedited videotapes related to ACORN offices in California
Was the California Attorney General's Office's investigation into the full, unedited videotapes successful in exonerating ACORN?
The report found there was no evidence of criminal conduct on the part of ACORN employees nor any evidence that any employee intended to aid or abet criminal conduct.

Question: What year did that happen?
Self-contained rewrite: What year did the California Attorney General's Office report that there was no evidence of criminal conduct on the part of ACORN employees nor any evidence that any employee intended to aid or abet criminal conduct?