Records obtained from Elections Canada suggest the agency has deepened its investigation into donations to Conservative MP Dean Del Mastro.

Lists of contributors to Del Mastro's 2008 federal campaign have been seized by the commissioner of Canada Elections, the records show. If the commissioner thinks criminal charges are warranted, he can refer the case to the director of public prosecutions, who decides whether to press charges.

The investigation seems to relate to allegations reported by Postmedia and the Ottawa Citizen that employees of a company owned by Del Mastro's cousin were reimbursed by the company for donations to Del Mastro's campaign. It's illegal in Canada to conceal the source of a donation to a candidate.

The seized records include names and addresses for some of the donors to Del Mastro's 2008 campaign. An undated stamp notes the seizure and lists a file number along with the name of the investigator. The name appears to be that of Ron Lamothe, who was previously reported to be the investigator assigned to Del Mastro's case.

It also seems to contradict Del Mastro's assertion that the investigation was over when it was referred to the commissioner's office in April.

Other documents filed in court by Elections Canada last year suggested Del Mastro exceeded his 2008 election campaign expense limit and that he filed a false document.

Del Mastro said he didn't do anything wrong in his campaign.

"It was a very interesting story, but I can tell you that I have zero knowledge of any such thing," he said about the donations in an interview with CBC News.

"What I can tell you is every cheque we received in our campaign is fully documented, was received in the proper form, it was properly receipted, it was properly reported. It's all public record and I'm proud of that. I'm proud of the fact we followed all the rules, I'm proud of the fact that we ran a clean campaign."

Investigation 'virtually complete'

Del Mastro provided an email to CBC News earlier this month that said the commissioner's office was about to receive the file.

An email from Elections Canada to Del Mastro's lawyer Jeffrey Ayotte, dated April 8, 2013, and provided to Evan Solomon, host of CBC News Network's Power & Politics, confirms the first stage of the probe was nearly finished.

"Our investigation is virtually complete, although odds and ends can still be found to follow up. The matter is going to the commissioner for review and consideration now. I cannot predict how long that process will take," the note from investigator Al Mathews reads.

Yves Côté, the commissioner of Canada Elections, has two options: he could accept the report, or he could refer the report to the director of public prosecutions, who could then decide to lay charges.

Del Mastro said the investigation should be over by now. He has complained to House Speaker Andrew Scheer that his privilege as an MP has been breached by the investigation, and said he wants to clear his name.

New Democrat MP Paul Dewar said it appears the investigation is moving beyond Elections Canada and the question is where it stands.

"That's interesting, because we certainly didn't get that indication from when we've asked questions in the House to Mr. Del Mastro or the Conservative government," he said of the seized records.

In the interview on Power & Politics, Del Mastro insisted he has done nothing wrong and expressed confidence he will be exonerated.

"I've been patient because I've been waiting for Elections Canada to go through the evidence I've provided. I've answered every question they've asked, I've provided every piece of evidence that they've requested. I've had absolutely nothing to hide from them in any regard," he told Solomon.

"Some months ago, they indicated to us that they had completed the investigation and still, here we are with no word from Elections Canada."

Initial step over

The investigation by Elections Canada is simply the first step in a process that has taken years in other cases, with the probe by the commissioner of Canada Elections coming after.

Del Mastro also insisted to Solomon that a personal cheque he wrote to Holinshed Research Group for $21,000 — that allegedly exceeds the $2,100 legal limit for candidates' contributions — was only a "deposit cheque that was fully reimbursed by the [riding] association and the campaign."

But there is no sign of that reimbursement in the records filed with Elections Canada.

Del Mastro also addressed the false-document allegation based on handwriting on a receipt from Holinshed that appeared similar to the handwriting of his official agent, Richard McCarthy. He said his agent wrote on top of a "stub" from the company to account for the transaction, and called the suggestion it's a false document "preposterous."

An investigator for the agency says in court documents that he believes Del Mastro knew he'd spent too much and tried to cover it up. The agency is also investigating Richard McCarthy, Del Mastro's official agent, who handled money on his behalf during the campaign and filed records with Elections Canada. In affidavits, the investigator said he believes McCarthy knew Del Mastro spent too much but submitted an erroneous election claim anyway.

None of the allegations have been tested in court, and no charges have been filed. The affidavits were filed to obtain production orders as part of the investigation.

With files from Kathleen Harris