A dozen police cruisers were vandalized Monday with painted words that mentioned work contracts and negotiations. (CBC)

A dozen police cruisers were vandalized overnight in Gatineau, Que., and fingers are being pointed at the city's police officers.

The cruisers were covered with orange paint.

Both the city and the officers' union said the officers could have been behind the vandalism, because words written in the paint referred to negotiations and work contracts.

For more than two years, police in Gatineau have been without a collective agreement.

Their protest has consisted of wearing cargo pants and khakis instead of police-issue slacks, but the mayor said he thinks it's possible that the vandalized vehicles mark another step in the protest.

While the cars are being washed, said Mayor Marc Bureau, they'll be out of commission.

Neither the union nor the city, however, has confirmed officers were involved in the vandalism.

Jean Pierre Bussière, the union's vice-president, said there will be an investigation, but the vandalism is probably a simple sign of frustration.

"You know, in my understanding, it was probably a way to inform the people on what's happening – that the city … they're doing nothing to end the conflict."

Bussière said he's not sure applying poster paint could be considered vandalism because it could easily be washed off.

On Friday, Gatineau police officers who were being sworn in at the Elgin Street police station said they would be willing to wear their proper uniforms when they conduct investigations on the Ottawa side of the river.

But on the Gatineau side, they said, they planned to continue their plainclothes – or at least pants – protest.