Party officials have isolated two IP addresses that were at the root of an attempted cyber-attack on the party's electronic voting system, causing extensive holdups and aggravating voters both at the convention in Toronto and across the country.
Party officials insisted the integrity of the voting system was not harmed, but acknowledged that the would-be hacker managed to "mess" it up enough to cause lengthy delays.
"The system has not been compromised," said former party national director Brad Lavigne. "The system was not hacked. It was never even close to being hacked."
Lavigne said someone outside the party tried to get access, triggering alarms that caused the system to shut down.
"The analogy that can be used is that somebody was trying to break into our house and the alarm went off and the robbers were scared away."
Lavigne stopped short of suggesting someone was deliberately trying to sabotage the NDP leadership process.
"I'm saying that somebody outside of the party was attempting to mess with our one-member, one-vote (system), but that the sanctity of our system was preserved because of the failsafes," he said. "The only thing they were able to achieve was a little delay."
Those delays persisted into the evening, when persistent slowdowns on the website forced the party to extend voting on the fourth and final ballot to ensure everyone had a chance to make their choice, said NDP spokeswoman Sally Housser.
"It wasn’t worse than last time," Housser said.
"As soon as we identified the problem, we fixed it. We've got a crack team of IT people troubleshooting. we were able to, similar to before, identify the problem, fix it and some of our colleagues back stage were able to vote fine."
It was just the latest example of high-tech mischief that's been plaguing Canadian politics of late.
The federal Conservatives have been under a barrage of allegations that election-campaign operatives used robocalling tactics to deliberately confuse voters to suppress support for their opponents in certain ridings.
Elections Canada is investigating reports that voters in Guelph, Ont., received calls from a phone number with a 450 area code directing them to the wrong polling station. Phone records show the number behind the Guelph calls was the same one registered to "Pierre Poutine'' of "Separatist Street'' in Joliette, Que.
Former Liberal party staffer Adam Carroll, meanwhile, was forced to quit after using a House of Commons computer and an anonymous Twitter account to disclose a Conservative cabinet minister's divorce details online.
The account was set up in the wake of the introduction of an online surveillance bill that would give authorities expanded powers to gain people's Internet information, drawing the ire of critics who said it was too intrusive.
Jamey Heath, campaign manager for third-place contender Nathan Cullen, said the NDP's chief electoral officer confirmed earlier Saturday that someone was messing with the system.
He said he was told "they did isolate it to two — or it may have been three — IP addresses, but they've resolved it."
Party president Rebecca Blaikie insisted that while the attempted attack proved a nuisance to the party and its voters, it did not penetrate the system nor compromise the voting results.
"Whoever this is or whatever it came from, their goal was simply to make it a pain to get into our site, to make it harder for people to vote, to block it up with a lot of traffic," Blaikie said.
"But traffic has nothing to do with security and so the vote itself is fine. It's just meant that we've had to have a lot more patience today than we thought."
Earlier, officials would say only that the system had been overwhelmed due to an unanticipated crush of voters all trying to cast their online ballots at the same time.
But that explanation was met with skepticism, since fewer than 10,000 New Democrats actually voted electronically on Saturday; the vast majority, some 56,000, had cast their ballots in advance.
The party hired Scytl, a Spanish-based company that specializes in electronic voting security, to run the online voting system.
Results from the second round of voting were delayed about two hours to give every member who wanted to vote a chance to do so.
For those who voted in person at the convention, lengthy lineups at voting stations formed as the delays pushed balloting well into the afternoon.
Lorne Nystrom, Thomas Mulcair's campaign co-chairman, said he was not overly surprised to discover someone was trying to thwart the party's democratic process.
"I'm beyond surprises," he said. "These things happen, it happens every day in this country and around the world and so I'm not surprised, but we'll get through it."
When fourth-ballot results were finally announced, front-runner Thomas Mulcair emerged the victor over second-place finisher Brian Topp. Nathan Cullen, Peggy Nash, Paul Dewar, Martin Singh and Niki Ashton were all knocked out of the race during earlier ballots.
Note to readers: Fixes third para to say integrity of voting system was NOT harmed