Hamilton police are poring over boxes full of ballots, credentials forms and other election-related material as part of an ongoing investigation into a local PC party nomination.

A document leaked to CBC News shows Hamilton police had a search warrant to obtain two cardboard boxes — one with ballots, one with credentials forms — from the May 7 nomination meeting for Hamilton West-Ancaster-Dundas (HWAD).

Police also examined a large volume of emails and two USB drives containing digital versions of those emails. The party says it voluntarily handed over the materials to investigators at its lawyer's Bay Street office in Toronto on Oct. 27.

The move is part of an ongoing police investigation into a provincial nomination meeting in Ancaster in May.

Ben Levitt became the candidate that night for next June's provincial election. But two of his challengers — Vikram Singh and Jeff Peller — alleged the party stuffed ballot boxes so Levitt would win.

The party refutes this, and says leader Patrick Brown can choose whatever candidate he wants, regardless of the outcome of a nomination meeting.

Peller and Singh both asked the party to review the nomination, but on June 3, Brown certified Levitt as the candidate.

Both then asked the court for a judicial review. Peller dropped his case last month, while Singh's will be in court again on Dec. 12.

Police confirmed in August that they were looking into the matter. Const. Lorraine Edwards said officers are examining to see if there is any possible criminal wrongdoing. She also confirmed the ballot seizure.

Investigators will be working on this for a while, Edwards said. "It's going to take some time."

The PC party says it's co-operating with the investigation. After concerns earlier this year, it says, Brown brought in Pricewaterhousecoopers to oversee future nominations.

"We have been providing assistance in regard to the investigation," party president Rick Dykstra said this month. "We will continue to remain open and transparent should there be any further requests."

The Ontario Liberals, meanwhile, are getting more vocal about the matter. The party called on the PCs Monday to reveal which witnesses have been interviewed and what Conservative officials are being investigated.

Singh's court application, which is separate from the criminal investigation, names Brown, party executive director Bob Stanley, Dykstra and staffer Logan Bugeja.