The Coalition Avenir Quebec is going after the Liberals for hiring a former CAQ staffer.
Yan Plante, who has a lengthy career as a political aide, was hired in August to work for Premier Philippe Couillard.
He left his post as political advisor to Francois Legault at the end of July, citing ideological differences with the direction the CAQ was taking.
Now the CAQ is taking legal action, accusing Plante of stealing confidential party documents by emailing them to his personal account in the weeks before his resignation.
The party has sent cease and desist letters to Plante and to Jean-Louis Dufresne, chief of staff for the Premier.
Those documents include the election strategy for the opposition party, as well as documentation on the party's internal structure.
"We're taking these measures because we think there is a breach made by Yan Plante on his obligation of loyalty and confidentiality about his ex-employer, the CAQ," said Simon Jolin-Barrette.
If this sounds familiar, it's because the same thing happened in August,.
Former CAQ staff member Frederick Schautaud was accused of copying confidential party documents and applying for a job with Dominique Anglade, the Liberal economic development minister.
The Liberals did not hire Schautaud.
As he did in August, Premier Philippe Couillard said the CAQ should not worry about what former staff members bring with them to new jobs.
Instead, he said that Francois Legault should wonder why his staff wanted to quit.
"The true question is why are people leaving his party, why are people leaving him in such a large number? And we keep receiving calls by the way. The reason is the people who believe in both Quebec and Canada do not feel welcome at the CAQ," said Couillard.
He added that neither Schautaud nor Plante gave the Liberal party any documents.
In leaving the CAQ for the Liberals, Plante was joining a growing list of former CAQ members including Anglade, Gaetan Barrette, and Sebastien Proulx.
Plante spent less than one year working for the CAQ. Prior to that he was an aide to federal Conservative Minister Denis Lebel.