A laptop and several memory sticks used to program Philadelphia’s voting machines were stolen from a city warehouse in East Falls, officials confirmed Wednesday, setting off a scramble to investigate and to ensure the machines had not been compromised.

Though it remains unclear when the equipment was stolen, sources briefed on the investigation said the items vanished this week. The laptop belonged to an on-site employee for the company that supplies the machines. It and the USB drives were the only items believed to have been taken.

City officials vowed Wednesday that the theft would not disrupt voting on Nov. 3.

“We are confident,” said Nick Custodio, a deputy to Lisa Deeley, chair of the city commissioners, who oversee elections, “that this incident will not in any way compromise the integrity of the election.”

But behind the scenes, they fretted about how President Donald Trump and his allies might use the news to cast doubt on the integrity of the city’s elections in light of false claims and conspiracy theories he cited during Tuesday’s presidential debate.

The commissioners initially refused to confirm the theft or that an investigation had been opened. They only did so after The Inquirer informed them it would be reporting the incident based on sources who were not authorized to publicly discuss it.

Philadelphia police referred all questions to Mayor Jim Kenney’s office.

“Since being informed of the incident, I have immediately committed to making necessary police resources available to investigate this incident and find the perpetrators. I have also committed to the city commissioners additional resources to provide enhanced security at the warehouse going forward,” Kenney said in a statement. “This matter should not deter Philadelphians from voting, nor from having confidence in the security of this election.”

Trump, who trails former Vice President Joe Biden in Pennsylvania polls, has sought to cast doubt on the integrity of the election and has specifically targeted Philadelphia, falsely saying Tuesday that Republican poll watchers had been turned away by the city’s election staff.

His rhetoric has alarmed experts and voting rights advocates, who say the president is undermining public confidence in the electoral system and inappropriately politicizing the democratic process.

Many details surrounding the stolen technology in Philadelphia remained unclear Wednesday, including how the equipment was taken, whether there are any suspects, and whether any machines had been compromised.

Custodio, the deputy to Deeley, said officials ensured the stolen laptop had been disabled remotely after the theft was discovered to prevent it from being used and added that it “did not have any of our election material on it.”

His statement did not address the stolen memory sticks, which are used to program the machines in advance of an election, including setting the design of the ballots.

The flash drives are encrypted to prevent tampering, and specifically matched with individual voting machines, said a spokesperson for Election Systems & Software, the voting machine vendor, adding: “Upon programming, these encryption keys ‘marry’ the USB with the machine, and if placed in another machine, it will cause an error and the machine will not work.”

Philadelphia has 3,750 of the ExpressVote XL touchscreen voting machines, and elections staff have begun programming them so they are ready to use on Nov. 3. The flash drives are inserted into the top of the machines; some of them are used to record the electronic votes used for unofficial results on election night, but it was unclear whether those stolen served that function.

Once a machine has been set up, it’s closed with a numbered seal. That means that any voting machines that are opened after being programmed should be identifiable because they would have broken seals. The commissioners have begun checking all the seals on the machines, which are numbered to prevent them from being opened and simply replaced, Custodio said, to ensure they have not been tampered with.

Sources familiar with the investigation said late Wednesday that during the review, officials found several machines had the wrong seal numbers, but Custodio said they believe the discrepancies were due to a logging error in recording the numbers and did not indicate that the machines had been compromised.

Those machines, he said, “will be thoroughly examined, wiped, and tested just to be sure.”

Philadelphia’s voting machines are fairly new, used for the first time last November. Gov. Tom Wolf ordered every voting machine in Pennsylvania, including those in Philadelphia, be replaced in advance of the 2020 election with more-secure machines that leave a paper trail that can be audited or even individually recounted by hand.

That means there’s a paper record of every vote cast, officials said. In the event of an audit or recount, it is the text on the ballots that is counted, not the bar codes or the electronic tallies.

“All voting systems have voter-verified paper ballots, which can be audited or recounted and are the official vote of record,” Wanda Murren, spokesperson for the Pennsylvania Department of State, said in a statement. “We are confident that Philadelphia, working with the department and our many partners, will be able to conduct a secure and fair election for its voters on Nov. 3.”

The discovery of the theft came during a particularly bad week for Philadelphia’s elections officials.

On Tuesday, the city opened its first-ever satellite elections offices to allow voters to cast mail ballots in person — and the statewide voter database went down moments after the celebratory news conference. That afternoon, Trump falsely accused Philadelphia of blocking his poll watchers from the offices, and again put a target on the city by repeating the claims during the presidential debate.

Voting via mail ballots has begun in Philadelphia, including at the satellite elections offices opened Tuesday, which city and state officials do not consider to be polling locations. .

Still, Trump said falsely on Twitter and in the debate that his campaign’s poll watchers had been blocked from observing early voting, accused the city of corruption, and encouraged his supporters to monitor in-person voting.

A lawyer for the campaign sent a letter to the commissioners late Tuesday threatening legal action if they are not allowed to observe the elections offices.

City officials are urging anyone with information on the stolen laptop and voting machine memory sticks to contact the Philadelphia police at 215-686-TIPS.