Vancouver police are beefing up the number of mounted officers patrolling Stanley Park after four suspicious fires have been set in the park since Thursday.

Police say the fires are linked and the works of an arsonist.

Const. Cinda Michael said 13 officers are now patrolling the park on horseback.

“We have seven regular officers who are supplemented by six reserve officers,” she said.

The fires were set at different locations, including near the Rose Garden and Beaver Lake.

A fire at the Brockton Oval, a sports field popular with cricket players, caused the most damage. It was lit under the bleachers and scorched the bench area and the side of a building.

Park Board commissioner Ian Robertson called it “despicable.”

“We got flames that were six- to eight-feet-high and this whole building is all wood structure and could have gone up in a matter of minutes,” he said.

Witnesses told police they saw a man riding a bike near the fires, but investigators have no suspects yet.

Michael said the recent dry spell is the worst she’s seen in her six years patrolling Stanley Park.

“It makes me feel a little bit apprehensive,” said Michael.

“But we’ve gone through dry summers before without incident and I have confidence in our patrols and in the public’s willingness to help us with this issue.”

Michael asked that the public be aware of the smoking and barbecue bans and to be vigilant.

“We’re really doing our best to make sure there are no accidents,” said Michael. “(Stanley Park) is something that none of us want to lose.”