Authorities in St. Louis are investigating an arson at a predominantly black church that was also vandalized with racist graffiti.

Firefighters were called to the Greater St. Paul Missionary Baptist Church just before 2 a.m. Tuesday after a building alarm sounded, and found the church on fire.

A back door had been forced open at the church in north St. Louis and there was racist graffiti on the exterior of the building, police said Wednesday. The interior of the church had an estimated $75,000 in damage.

The St. Louis Regional Bomb and Arson Unit is leading the investigation. Messages seeking comment from the church pastor, Titus D. Irving, were not immediately returned. The church has about 200 members.

A string of arsons last October at churches in predominantly African-American parts of the St. Louis region prompted a hate crime investigation.

Authorities eventually charged David Lopez Jackson with two counts of second-degree arson. But authorities said after the arrest of Jackson, who is black, that there was no indication of a hate crime. Jackson remains jailed while awaiting trial.

Race relations in the region remain tense nearly two years after the police shooting death of 18-year-old Michael Brown in Ferguson, a St. Louis suburb, and a grand jury's subsequent decision not to charge the officer who shot him.

Brown was black and unarmed when he was shot by white Darren Wilson on Aug. 9, 2014, in a case that helped spur the national "Black Lives Matter" movement. The shooting also renewed concern about the treatment of minorities in and around St. Louis.