VANCOUVER -- Police in Vancouver say they're investigating a spike in local church vandalism after more than a dozen incidents have been reported to officers since early June.

Investigators are looking into 13 incidents of mischief and vandalism at churches and church properties since June 2, Vancouver police said in a news release Thursday. Some of the reports include rocks being thrown at windows, graffiti and threats of buildings being set on fire.

"Fortunately, nobody has been hurt in these Vancouver incidents and most of the damage has been minor," said Sgt. Steve Addison in the news release.

"However, we’re growing more concerned each day by the escalation of these crimes and their brazen nature, and we’re calling on the people responsible for these crimes to stop. There are more productive ways to voice your anger and express your views."

One of the reports was of a church being vandalized on June 8 at about 9 p.m. near Little Mountain. According to police, four people dressed in black threw red paint on property and painted graffiti that referenced residential schools.

On Canada Day, two women reportedly threw orange paint at the side of a church building in the Renfrew-Collingwood neighbourhood.

Additionally, police said someone threatened to burn down a church on Canada Day and, on July 20, the pastor of a church in South Cambie spotted a gallon of lighter fluid and rags near the side of the building early in the morning. The pastor reportedly saw a man standing in the middle of the road staring at the church that same morning.

No arrests have been made and investigators are gathering evidence and looking for any possible links between the incidents.

At least six other churches in B.C. were destroyed or damaged by flames in the past month. Mostly recently, a Surrey church was destroyed in what police are calling a suspicious fire. 

Some have speculated that the recent church destruction and vandalism could be connected to discoveries of unmarked graves at former residential school sites across the country as most of the schools were run by the Catholic Church.

The schools were known for overcrowding, poor sanitation, unhealthy food and menial labour. Harsh punishment was given to students who spoke their native language or took part in traditional ceremonies.

"We’re reminding people to be proactive and to report anything unusual at church properties, because we’re concerned this could escalate into a situation where someone gets badly hurt," Addison said.

"If you see anyone who looks suspicious and you think they’re about to commit a crime, please don’t hesitate to call 911."