ST. THOMAS, Ont. - Police say thieves broke into four churches in St. Thomas, Ont., during the nighttime hours on Christmas Day and into the weekend and it's believed the burglaries are related.

In each case, the churches were entered through basement windows and the thieves searched for donation envelopes, broke into locked areas and ransacked offices.

The churches robbed in the southwestern Ontario city were St. John's Anglican Church, Centre St. Baptist Church, Trinity Anglican Church and St. Thomas Pentecostal Assembly.

Police are calling other churches in St. Thomas to alert them, and to advise them to take security precautions.

Police did not disclose the amount taken in the four burglaries.

Churches have been broken into before in St. Thomas but police say the weekend string of thefts is unheard of.

"It's pretty terrible," Staff Sgt. Hank Zehr said.

"I can't think of anything like this -- four in two days."