"This data, alleged to have been taken from 407 ETR, may have been used by candidates to further their electoral success," said NDP provincial secretary Karla Webber-Gallagher. "This is a violation of the laws of Ontario that govern how personal, private information is collected and used."

The 407 ETR said the personal information of roughly 60,000 people was stolen from its offices "some time over the past 12 months." A member of the public reported the alleged theft to the company last Thursday, said spokesman Kevin Sack.

Sack confirmed that Sandhu worked in one of the company's accounting departments but left the firm in February. He could not say if Sandhu's departure was linked to the alleged theft.

"We're solely focused on our customers," Sack said. "And getting them what they need to feel comfortable and confident with our security and their information. So, no, I don't have any information about allegations concerning (Sandhu)."

Bob Nichols, spokesman for the Ministry of Transportation, said the matter is now the subject of an active police investigation — a fact confirmed by York Regional Police.

"The Ministry and 407 ETR take their responsibilities for the protection of personal information seriously," he said. "407 ETR has taken appropriate steps to deal with the breach."

NDP Leader Andrea Horwath said Ford needs to answer questions related to the alleged data theft.

"What has Mr. Ford done as leader of the Conservative Party to follow up when it comes to the data and the breach of data?" she said. "Has he gotten a hold of the information and privacy commissioner … has he contacted the police? ... Lots of questions need to be answered by Mr. Ford on this issue."

Speaking in Ottawa, Liberal Premier Kathleen Wynne called the alleged data theft "disturbing."

"I think it's clear that the people of Ontario need to know what the vetting process is for candidates and how such a thing could happen," she said.

Ford also came under fire for attending a party fundraiser in violation of campaign rules. The Tory leader said he was "very clearly misinformed," had dismissed the person organizing the event and said his party was conducting an internal investigation. He also said anyone who made donations related to the event would get their money back.

"I take Elections Ontario very seriously, the rules," he said. "We'll put new protocol, better protocol in place to make sure this doesn't happen again.... I take this seriously."

The Liberals said late Thursday afternoon that they had asked Elections Ontario to investigate Ford's appearance at the fundraiser.

Ontario heads to the polls June 7.

By Shawn Jeffords, The Canadian Press