Updated

St. Louis' police chief said Tuesday officers were stepping up patrols and developing profiles of possible suspects in a spate of fires that have damaged six churches in largely black neighborhoods in the past two weeks.

The St. Louis Post-Dispatch reports Sam Dotson's announcement came the same day the reward for information leading to an arrest doubled to $4,000.

Dotson says churches damaged during the suspicious fires Oct. 8 through Oct. 18 vary denominationally and are within five miles of each other. Four are on St. Louis' north side, and two are in nearby Jennings.

Church leaders said they are focused on healing, not speculating about blame.

"This is a spiritually sick person," said the Rev. David Triggs, whose New Life Missionary Baptist Church in St. Louis was set on fire on Saturday. "This is a sin issue. It's not a race issue."

John Ham, a spokesman for the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives, said the agency is investigating, along with St. Louis city and county arson squads. The ATF has jurisdiction over fires at all houses of worship, Ham said.

The Rev. Rodrick Burton of New Northside sensed an "apathetic" response to the fires locally, though a few neighboring churches have offered to lend a hand. He said no one knows if the fires were racially motivated, but that it's clear they're an attack on religious freedom.

"Whether you practice faith or you don't, everyone should be very concerned about that," Burton said. "Religious freedom is part of our identity as Americans."

The Associated Press contributed to this report.