The RCMP investigation into alleged voter fraud in the 2017 United Conservative Party leadership contest has now expanded to Edmonton.

CBC News has confirmed at least three RCMP officers have conducted unscheduled interviews with UCP leadership voters from the South Asian communities in Mill Woods.

One UCP member, who requested confidentiality, told CBC News that two RCMP plainclothes officers, a woman and a man, arrived unannounced at his Mill Woods home Thursday evening.

"They said, 'I'm here from the RCMP. And you heard, maybe, about the inquiry going on about the Jason Kenney campaign in 2017,'" the man said, adding that one officer later asked him if he had voted for Kenney.

"They even asked that question; I don't know if it's a valid question or not," he said. "But I said, 'Yes, I did.'"

The voter said he was asked if he understood the voting process employed by the UCP for the leadership contest.

"'Did you know the process to send the PINs? How did you vote?'" the voter said the officers asked.

"I said, 'Yeah, I voted. I don't remember, maybe with an email or a text message, it was either one of them,' '' the man said he told them.

"So those were the questions. They were satisfied. They just wanted to know, is it valid, is it legit?"

He said the officers also asked him to provide his email address and phone number, then cross-referenced the information he gave with a list they already had.

Asked to confirm relatives' identities and addresses

Another UCP voter, who also requested confidentiality, said two plainclothes investigators came to the door of his Mill Woods home Thursday afternoon.

"They gave the whole rundown about the UCP leadership race, how some people were illegally voting for others," he said, adding that he confirmed he had voted using his own email address.

He said the two male officers, one of whom was from the Airdrie detachment, were working from a long list of names.

The man said the police told him they were contacting everyone on the list to verify if they had in fact voted in the UCP leadership race. He confirmed the officers also spoke with his parents.

Both UCP supporters said the RCMP asked them to look at part of the list and confirm the identities and addresses of their relatives, who live in the same households. Both voters said they told the RCMP officers they had voted with their relatives.

Earlier this month, RCMP executed a search warrant and seized a computer from an auto-repair business owned by newly elected Calgary MLA Peter Singh. Singh's lawyer later confirmed to CBC News that the RCMP did so as part of its investigation into allegations of voter fraud during the UCP leadership contest.

Through his lawyer, Singh denied any wrongdoing.

Emails fraudulently attached to UCP memberships

CBC News has previously reported that documents showed email addresses fraudulently attached to UCP memberships had been used to cast ballots in the party's leadership race, which premier-designate Jason Kenney won in 2017.

There were virtually no safeguards against the practice.

To choose a leader, UCP members submitted their votes online. To do so, each member was supposed to have a verified email address and a PIN number.

CBC News reviewed a list of more than 100,000 UCP members and their email addresses. Forty-nine addresses were selected because of their suspicious domains. And of those, 31 had been used to cast leadership votes.

Many of the suspect domains trace back to a hosting service and are linked to a network of ever-changing websites and domains, including Torytracker.com, Bellwebmail.com, Mail.deanfrench.ca and many more. It is not known who purchased those domains.

The email addresses were then cross-referenced with a list of people registered to vote in the leadership race and a list of those who actually voted.

Members confirmed they didn't vote

Cross-referencing two of the party lists obtained by CBC News shows the vast majority of the fraudulent emails were attached to memberships between Oct. 3 and Oct. 24, 2017.

The suspect email addresses attached to members were all purchased in the days leading up to the leadership vote on Oct. 28, 2017. None of the emails are currently in service.

It is not known how widespread the practice was outside of the selected sample, and there could be more fraudulent emails with valid domains like Gmail or Hotmail.

CBC News contacted a dozen people with suspect emails attached to their memberships who confirmed they did not vote in the leadership race, and said their emails were different from the ones on the list.

Former UCP MLA Prab Gill has alleged in a letter to the RCMP that the Kenney leadership campaign used fraudulent emails to receive personal identification numbers needed to cast ballots in the leadership race. Gill said those PINs, which should have been sent to individual members, were then used by the Kenney campaign to vote for Kenney.

CBC News has not independently verified Gill's claims.

A cease-and-desist letter sent to Gill from Kenney's lawyer, Steven Dollansky, called the allegations "plainly false and defamatory."

In a written statement Friday, UCP executive director Janice Harrington said the party is confident in the integrity of the results of the leadership vote.

"When allegations regarding the leadership race were first raised, our party's legal counsel reached out the RCMP to offer them any assistance or information they require to conduct their inquiries," said Harrington. "We will continue to assist the RCMP as they conduct their due diligence."

Investigations into alleged illegal donations

On March 15, CBC News revealed Alberta's Office of the Election Commissioner had asked the RCMP to investigate allegations of irregular political contributions involving the so-called "kamikaze" campaign of United Conservative Party leadership contender Jeff Callaway.

The elections commissioner's office called in the Mounties after it identified what it said were "potential violations that fall outside of the jurisdiction of our office."

The election commissioner's office is continuing its own investigation of irregular financial contributions to Callaway's campaign and has already issued $31,000 in fines to four people for making, or facilitating, illegal donations to the campaign. Two others received letters of reprimand.

On March 16, CBC News revealed Callaway ran a "kamikaze" campaign in 2017 on behalf of Kenney, who won the party leadership on Oct. 28, 2017.

Internal documents obtained by CBC News, and subsequently by several other media outlets, show Kenney's campaign provided strategic political direction and resources, including attack ads, to Callaway's campaign for the express purpose of targeting Kenney's chief rival in the leadership race, former Wildrose leader Brian Jean.

The two campaigns had even planned for Callaway to drop out of the race before the vote, which he did, and then threw his support behind Kenney.

Both men deny Kenney's campaign ran Callaway as a candidate to attack Jean.

If you have information about this story, or information for another story, please contact us in confidence at cbcinvestigates@cbc.ca.