ABC News has reached out to all eight major Democratic presidential campaigns or exploratory committees to ask for comment on the allegation. Those major campaigns or exploratory committees include the eight candidates who are current or former elected officials.
The allegation was detailed in a statement released Wednesday by Vanessa Tyson, an associate professor of politics at Scripps College in California, who claims that the then 25-year-old Fairfax sexually assaulted her in a hotel room during the 2004 Democratic National Convention in Boston.
"On the night of Friday, February 1, 2019, I read multiple news accounts indicating that Virginia Lt. Governor Justin Fairfax would likely be elevated to Governor as an immediate result of a scandal involving Governor Ralph Northam. This news flooded me with painful memories, bringing back feelings of grief, shame, and anger that stemmed from an incident with Mr. Fairfax that occurred in July 2004 during the Democratic National Convention in Boston," Tyson wrote in a statement released through her legal team.
Fairfax vehemently denies the claim.
Thus far seven candidates, California Senator Kamala Harris, New York Senator Kirsten Gillibrand, New Jersey Senator Cory Booker, Massachusetts Senator Elizabeth Warren and South Bend, Indiana Mayor Pete Buttigieg, Hawaii Congresswoman Tulsi Gabbard and former Housing and Urban Development Secretary Julián Castro have all called for Tyson's claims to be investigated, but have not called for his resignation.
What entity would be responsible for an investigation into Tyson's claims remained unclear Friday, and no such investigation has been announced publicly.
"I think the letter written by the woman reads as credible account and I think there should be an investigation to get to the bottom of it and determine the facts," Harris told reporters on Capitol Hill Thursday morning.
Gillibrand commented on the situation Wednesday night during a taping of the "Lovett or Leave It," podcast, and was asked directly by host Jon Lovett if she believes Fairfax should resign, something she did not do.
"I think there has to be a full investigation, I thought her story was deeply disturbing and credible so there must be an investigation," Gillibrand said.
A spokesperson for Warren's presidential exploratory committee wrote in an email to ABC News Thursday, "Warren believes these allegations need to be taken seriously and supports an investigation into the claims."
Booker told CNN's Manu Raju Wednesday of Tyson, "It takes tremendous courage for someone to come forward in the way that she did...This is a deeply disturbing allegation that should be thoroughly investigated."
In an interview with NBC News' Chuck Todd Wednesday evening, Buttigieg said, "The allegations are extremely disturbing, horrifying in fact, and they deserve to be fully investigated."
Gabbard called for an investigation in a tweet Thursday night.
"I read Dr. Tyson's statement, I believe her, I believe her claim. He has denied that, my hope is that there's some process to understand what happened," Castro said on MSNBC Thursday.
When asked about the allegation against Fairfax by ABC News, former Maryland Congressman John Delaney said, "If I was a Virginian, I'd want some special elections."
While it has been less than a week since they have been known publicly, the allegation against Farifax present a particular challenge for Democrats trying to balance the proper response to claims that are difficult to fully investigate and corroborate.
In the immediate aftermath of her claims being made public, Democrats like Gillibrand, Harris and Booker called for an investigation into the claims made by Christine Blasey Ford, the California psychology professor who accused Brett Kavanaugh, President Trump's nominee to the U.S. Supreme Court, of sexual assault stemming from an incident when the two were in high school in the early 1980s. Kavanaugh denied the claims and was later confirmed by the U.S. Senate.
"The FBI needs to complete a non-partisan, factual investigation and issue a report to the [Senate Judiciary] Committee," Gillibrand said on September 18, "Then, the Committee should have a hearing."
On September 23, Gillibrand urged Kavanaugh to withdraw his nomination.
The FBI did later investigate Ford's claims against Kavanaugh, but her attorney's later called that investigation a "sham," since the FBI interviewed neither the accuser nor the accused.
"You cannot have an FBI investigation where you don't interview both the accused and the accuser," Ford's attorney Debra Katz told ABC News at the time. "That's not a credible investigation, and we're all the worse for it."
"When it was announced that the FBI could investigate these serious and credible claims allegations I had hoped that there would be a legitimate investigation," Harris said, "This should have been a search for the truth, they should have been allowed to do their full job."
"I believe Dr. Blasey Ford because she’s risking everything — her safety, her security, her reputation, her career — to tell this story at this moment for all the right reasons," Gillibrand said in a speech on the floor of the U.S Senate that same day.
"I want to thank you for your courage. And I believe you, I believe you, and I believe many Americans across this country believe you," Harris told Ford during the Senate Judiciary Committee hearing.
"You are speaking truth that this country needs to understand, how we deal with survivors who come forward right now is unacceptable," Booker told Ford during the hearing.
Harris, Gillibrand, Booker and Warren all eventually voted against Kavanaugh's confirmation to the Supreme Court.
Fairfax, a 39-year-old former federal prosecutor long seen as a rising star in Virginia politics, initially responded by calling the allegation a "smear" earlier this week, but on Wednesday Fairfax released a statement Wednesday saying he takes the situation "very seriously."
"Regarding the allegation that has been made against me – while this allegation has been both surprising and hurtful, I also recognize that no one makes charges of this kind lightly, and I take it and this situation very seriously," Fairfax wrote. "This has been an emotional couple of days for me and my family. And in my remarks on Monday, I think you could hear how emotional dealing with an allegation that I know is not true has been for me."
Fairfax did not respond to questions about Tyson's allegation on Thursday when asked at the state capitol in Richmond by ABC News' Tom Llamas.
Amid the Fairfax allegation is the seemingly constant cavalcade of controversy facing Virginia's other top two Democratic officials, Governor Ralph Northam and Attorney General Mark Herring.
Northam continues to remain in power despite near-universal calls for his resignation after a racist photo of a man in blackface and another in Ku Klux Klan robe appeared on his 1984 medical school yearbook page.
All eight major Democratic presidential candidates have called on Northam to step down.
However, in a sign that he is prepared to fight to keep his job, a spokeswoman for Northam confirmed to ABC News Wednesday evening that he has retained the Washington, D.C.-based PR firm IR+Media to advise him on crisis communications.
Herring meanwhile dropped another political bombshell on the state Wednesday, revealing in a statement that in 1980 he dressed up as rapper Kurtis Blow and wore "brown makeup," to a college party.
"In the days ahead, honest conversations and discussions will make it clear whether I can or should continue to serve as attorney general, but no matter where we go from here, I will say that from the bottom of my heart, I am deeply, deeply sorry for the pain that I cause with this revelation," Herring, who met Wednesday with African-American leaders in the Virginia state legislation, wrote in a statement.
ABC News also learned Wednesday that Herring has stepped down as a co-chair of the Democratic Attorneys General Association.