(CNN) A graduate student at the University of Wisconsin-Madison has resigned from a teaching position after admitting on social media that they falsely claimed to be a person of color.
CV Vitolo-Haddad apologized last week in two posts on Medium and announced that they were leaving their position as the co-president of the university's Teaching Assistants' Association (TAA). Vitolo-Haddad uses the nonbinary pronouns they/them.
The apologies came after an anonymous post on Medium accused Vitolo-Haddad of misleading people about their racial and ethnic identity.
In a September 6 post addressed to "dear friends, loved ones and organizing comrades," Vitolo-Haddad wrote that they were "so deeply sorry for the ways you are hurting right now because of me."
"I have let guesses about my ancestry become answers I wanted but couldn't prove. I have let people make assumptions when I should have corrected them," Vitolo-Haddad wrote.
In a second post that was edited on September 11, Vitolo-Haddad wrote that they were of southern Italian/Sicilian heritage.
"It was my choice and error to identify any differently," Vitolo-Haddad wrote.
CNN was not able to reach Vitolo-Haddad for comment.
"When asked if I identify as Black, my answer should have always been 'No.' There were three separate instances I said otherwise," Vitolo-Haddad wrote, adding that "I should have never entered Black organizing spaces."
"They are not my place. Once realizing this, it wasn't sufficient to just leave; I should have explained that directly to the people who invited me and clarified my identity," Vitolo-Haddad said.
Vitolo-Haddad also apologized for "taking lies about Cuban roots at face value."
Vitolo-Haddad was offered a conditional tenure-track position at California State University, Fresno, and was scheduled to start teaching during the 2021 fall semester, a university spokeswoman told CNN. The offer was made before the allegations were made public and was subject to Vitolo-Haddad completing a background check.
"We can confirm that CV Vitolo-Haddad will not be a faculty member at Fresno State," said spokeswoman Patti Waid.
TAA Madison confirmed that Vitolo-Haddad had resigned and said in a statement that it was discontinuing events that Vitolo-Haddad was directly involved in organizing.
"We condemn CV Vitolo-Haddad's appropriation of Black and Brown identities in no uncertain terms," the union said in its statement. Vitolo-Haddad is not listed as an officer on the TAA website.
"The TAA enabled this harm by electing them to a position of power in our union: we have unknowingly rewarded the toxic opportunism of performing Blackness. We intend to immediately begin the work of repairing this harm," the statement said.
John Lucas, the university's assistant vice chancellor of university communications, told CNN that Vitolo-Haddad is not currently employed as a teaching assistant and is a doctoral student in the university's journalism and communications school. Vitolo-Haddad received a bachelor's degree from the University of Central Florida and a master's degree in communications from Wake Forest University, according to their LinkedIn profile.
"UW--Madison expects that people represent themselves authentically and accurately in all aspects of their academic work," Lucas said.
Earlier this month, Jessica Krug, who was an associate professor at George Washington University, admitted pretending to be Black for most of her adult life, when she was actually White, Jewish and from a Kansas City suburb.
She was a history professor specializing in Latin America and Africa until she resigned last week.
Krug earned her doctorate in 2012 from the University of Wisconsin-Madison, according to her George Washington University staff page, which is no longer on the website.