A computer server central to the 2016 election was quietly wiped clean by its custodians just after a lawsuit was filed against election officials in the US state of Georgia.
The server's data was destroyed on July 7 by technicians at the Centre for Elections Systems at Kennesaw State University, which runs the state's election system.
The data wipe was revealed in an email sent last week from an assistant state attorney-general to plaintiffs in the lawsuit. More emails obtained in a public records request confirmed the wipe.
The lawsuit, filed on July 3 by a diverse group of election reform advocates, aims to force Georgia to retire its antiquated and heavily criticised election technology.
The server, which was a statewide staging location for key election-related data, made national headlines in June after a security expert disclosed a gaping security hole that was not fixed six months after he reported it to election authorities.
Republican Secretary of State denies responsibility
It is not clear who ordered the server's data irretrievably erased.
The Kennesaw election centre answers to Georgia's Secretary of State, Brian Kemp, a Republican who is running for governor in 2018 and is the main defendant in the suit.
A spokeswoman for the his office said on Wednesday (local time) that "we did not have anything to do with this decision", adding the office also had no advance warning of the move.
The centre's director, Michael Barnes, referred questions to the university's press office, which declined to comment.
Plaintiffs in the lawsuit, who are mostly Georgia voters, want to scrap the state's 15-year-old vote-management system — particularly its 27,000 AccuVote touchscreen voting machines, hackable devices that do not use paper ballots or keep hardcopy proof of voter intent.
The plaintiffs were counting on an independent security review of the Kennesaw server, which held electronic poll book and other elections staging data for counties, to demonstrate the system's unreliability.
Wiping the server clean "forestalls any forensic investigation at all", said Richard DeMillo, a Georgia Tech computer scientist who has closely followed the case.
"People who have nothing to hide don't behave this way."
Election results could be untrustworthy
The server data could have revealed whether Georgia's most recent elections were compromised by malicious hackers.
The plaintiffs contend the results of both last November's election and a special June 20 congressional runoff — won by Mr Kemp's predecessor, Karen Handel — cannot be trusted.
Possible Russian interference in US politics, including attempts to penetrate voting systems, has been a national preoccupation since the Obama administration first sounded the alarm more than a year ago.
Mr Kemp and his GOP allies insist Georgia's elections system is secure. But plaintiff Marilyn Marks, executive director of the Coalition for Good Governance, believes the server data was erased precisely because the system is not secure.
"I don't think you could find a voting systems expert who would think the deletion of the server data was anything less than insidious and highly suspicious," she said
Server information may still be available
It could still be possible to recover relevant information from the server.
The FBI is known to have made an exact data image of the server in March when it investigated the security hole.
On Wednesday, the State Attorney-General's office notified the court of its intent to subpoena the FBI seeking the image, according to a court document that was emailed to lawyers in the case on Thursday.
Atlanta FBI spokesman Stephen Emmett would not say whether that image still exists, or whether agents examined it to determine whether the server's files might have been altered by unauthorised users.
Other backups appear to be gone. In the same email to plaintiffs' attorneys, assistant state attorney general Cristina Correia wrote that two backup servers were also wiped clean on August 9, just as the lawsuit moved to federal court.
Security hole left unfixed
A 180-page collection of Kennesaw State emails, obtained on Friday by the Coalition for Good Governments via an open records search, details the destruction of the data on all three servers and a partial and ultimately ineffective effort by Kennesaw State systems engineers to fix the main server's security hole.
As a result of the failed effort, sensitive data on Georgia's 6.7 million voters — including social security numbers, party affiliation and birthdates — as well as passwords used by county officials to access elections management files remained exposed for months.
The problem was first discovered by Atlanta security researcher Logan Lamb, who found it while doing online research in August 2016.
He informed the election centre's director at the time, noting in an email that "there is a strong possibility your site is already compromised".
Based on his review of the emails, Mr Lamb believes that electronic polling books could have been altered in Georgia's biggest counties to add or drop voters or to scramble their data.
Malicious hackers could have altered the templates of the memory cards used in voting machines to skew results.
An attacker could even have potentially modified "ballot-building" files to corrupt the outcome, said Mr Lamb.
One problem among many
To voting experts, this story is only part of a much larger problem.
The Department of Homeland Security says 21 states had elections systems scanned or penetrated by Russia-backed hackers last year, though there is no evidence they altered voting outcomes.
But computer security experts say it is possible Russians or other malicious actors have sown undetected booby traps in the highly decentralised US voting landscape.
In June, a leaked National Security Agency memo showed that 122 elections officials in various states were targeted with phishing emails crafted by Russian agents intent on stealing their passwords.
That revelation helped persuade Lamb to go public in the first place.