Shortly before Allred's news conference, Whitman had held her own news conference denying she ever received a letter from the Social Security Administration. She says she didn't know the housekeeper was an undocumented worker until last year, prompting her to fire the worker.
"Neither my husband nor I received any letter from the Social Security Administration. And if there is a letter out there, I don't know how they got it," Whitman said.
But the letter Allred held up during the news conference had a handwritten note at the bottom, saying, "Nicky, please check this. Thanks." The note was allegedly written by Harsh. It also appeared someone had started filling out the response to the Social Security Administration.
"Meg Whitman is exposed as a liar and a hypocrite. She should now apologize to Nicky, the press and the public for her blatant lie," Allred said.
In California, employers bear no responsibility to report illegal workers - only to not knowingly hire and employ them.
Whitman said she fired Diaz Santillan immediately after learning she was illegal in 2009. According to the former eBay CEO, she had no reason to question the housekeeper's status because she had provided what appeared to be valid documents when she was hired.
After the letter was made public, Whitman softened her denial.
"He does a lot of the processing of the household paperwork, and it would have been unusual if he'd say anything to me about it. So I don't recall him ever saying anything to me about it," Whitman said in an interview later Thursday on KNX am radio station 1070.
In a statement, Harsh said, "If, as she claims, she received this letter and note of inquiry from me, she never answered my request to look into this. Instead she chose to continue her deception."
"While I honestly do not recall receiving this letter as it was sent to me seven years ago, I can say it is possible that I would've scratched a follow up note on a letter like this," Harsh said in a statement.
Harsh also said neither he nor his wife believed there was a problem with the housekeeper's legal status, and he did not remember discussing it with his wife.
Whitman said she would be willing to take a polygraph test to prove that she was stunned to learn Diaz Santillan was an undocumented worker.
People have mixed feelings about the controversy.
"If you don't know about it, then that's not your fault, but, I don't know, there's things called background checks," said Hollis Tyde of San Francisco.
Ranzy Malouki of Los Angeles said he doesn't think the controversy will make a difference in the race for governor.
"We've seen it before, many times, in every race. There's always something that comes up, and it doesn't really change anything," he said.
A group of Hispanic legislative and education leaders held a news conference Friday afternoon. They are all Jerry Brown supporters. And they criticized Whitman's firing of her illegal housekeeper.
"The door shut on her very quickly when she acknowledged to Meg Whitman, 'I have a problem. I have a problem and I need your help,'" said state Assemblyman Kevin de Leon (D-Los Angeles).
The Whitman campaign issued a statement saying that Jerry Brown and his supporters should be condemning the exploitation of Diaz for political purposes.
Saturday's debate is sponsored by Univision and will be televised in Spanish.