ALBANY — Gov. Andrew M. Cuomo and the New York State Democratic Party both acknowledge the existence of a false piece of campaign material that wrongly implied that his primary opponent, Cynthia Nixon, was anti-Semitic. They say it went to 7,000 households, and cost about $11,000. And they both say it was wrong.

Beyond that, there had been few details about who was responsible for the flier’s language, delivery and its timing, coming before Rosh Hashana and before Thursday’s primary.

“As we have said this mailer was a mistake and completely inappropriate,” the party’s executive director, Geoff Berman, said in a statement on Monday. “The party does not discuss internal processes but we take this matter very seriously and are putting rigorous controls in place to ensure it never happens again.”

On Tuesday, the Cuomo campaign released a bit more about the mailer’s origins, identifying the creator only as “an individual helping the campaign on constituency outreach.”