The Federal Bureau of Investigation is offering rewards of up to $15,000 in the search for culprits in arson attacks at three Catholic churches in El Paso that largely serve Hispanics and migrants.

The first blaze was set outside the St. Matthew Catholic Church on May 7. Exactly a week later, incendiary devices were thrown at St. Patrick Cathedral, a spokesman for the Diocese of El Paso previously told NBC News.

Then, on June 15, firefighters encountered heavy smoke coming from the main sanctuary of St. Jude Catholic Church. They found a broken window near the chapel’s altar.

“We are counting on assistance from members of the community to keep our city safe,” the FBI said in a press release Thursday announcing rewards of $5,000 for information on each arson attack, or $15,000 for all three.

St. Jude Catholic Church. FBI

"Every lead will be thoroughly investigated. Regardless of how insignificant you think your information might be, we strongly encourage you to come forward and welcome your information and assistance," the FBI said.

The Federal Bureau of Alcohol, Tobacco, Firearms, and Explosives and local law enforcement offices such as the El Paso Fire Marshal’s Office and the El Paso Police Department are also investigating the string of fires.

The three religious institutions at the center of the investigation are affiliated with the El Paso Catholic Diocese, the first one in the U.S. to be led by a Hispanic Bishop.

The FBI's announcement comes about six weeks after a massacre in El Paso in which 22 people were killed at a Walmart by a gunman who admitted he was targeting people of Mexican descent.

Patrick Crusius, 21, of Allen, Texas, was indicted on capital murder charges earlier this month in connection to the mass shooting on Aug. 3.

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