OTTAWA—Conservative party officials have pinpointed candidate Brad Trost’s campaign as one potential source of a suspected leak of the party’s membership list.

But Trost’s campaign manager says an investigation on their end failed to uncover how the list allegedly given to the National Firearms Association could have come from them.

Party members had been complaining of being contacted by the NFA after the leadership race ended, arguing the only way the firearms advocacy group could have received their names was through the membership list.

Read more: Conservative party takes disciplinary action after membership list shared

The NFA was sent a cease-and-desist letter by the Conservative party’s lawyer this week but declined to comment when reached by The Canadian Press.

Trost campaign manager Joseph Ben-Ami says their team was told earlier this week they were “on notice” as the potential source.

He says they took the matter seriously but a review of their internal systems provided no evidence the list came from them.

Ben-Ami says they told the party as much on Monday but have yet to hear back.

Conservative party spokesman Cory Hann says the matter is in the hands of the committee that organized the race.

Ben-Ami says they’d like to know why the party believes the list came from the Trost camp, noting it was party officials themselves who put it together.

“We’re not asking them for proof in a confrontational way, we just want to know what their evidence is,” he said.

One hint could be in the names — the party “salted” each list of members given to the campaigns with fake information so they could trace any problems after the fact.

Nearly 260,000 people are members of the party, and around half cast ballots in the leadership contest which concluded last month with the election of Andrew Scheer.