At first, everyone thought it was a random act of madness like so many others that have scarred communities across America.
But now authorities believe 39-year-old Ronald Taylor, a black man accused of killing three people and wounding two others in a Wilkinsburg rampage on Wednesday, may have shot his victims because they were white.
The FBI has begun a preliminary civil rights investigation into the incident.
"We believe the shootings, from indications from news reports and statements from witnesses, may have been racially motivated," said Bill Crowley, spokesman for the Pittsburgh office of the FBI.
He would not discuss reports that Allegheny County police found racial epithets against whites inside Taylor's apartment and deferred questions to county homicide detectives, who have jurisdiction in the case. Lt. John Brennan of the county police confirmed that officers found "anti-white, anti-Jew" statements inside the apartment but wouldn't release the writings or discuss specifics.
Crowley said the FBI initially responded to the shootings to support local police. When the agents proved unnecessary, they left. But when reports began circulating that Taylor may have deliberately targeted whites and spared blacks, two agents returned to the scene Wednesday night to begin an investigation.
Some of those reports involved witnesses' statements that appeared in the media. John DeWitt, one of the men who went to Taylor's apartment to fix his door, said Taylor taunted him with racial slurs. When maintenance worker Andrew Williams asked why Taylor was carrying a gun, Taylor said he planned to use it because he "didn't like white people," according to Williams' wife, Charlene. Another witness said Taylor called a woman a "smart white bitch" while he was deciding if he would shoot her or someone else.
In addition, witnesses said Taylor told blacks that he wouldn't hurt them.
The Justice Department routinely monitors major crimes, getting involved if evidence comes forward, from any credible source, of civil rights violations.
The department may choose to investigate at any time but usually doesn't initiate a prosecution until after the case plays out in the state courts.
The Justice Department often monitors cases in detail without taking action. Despite pleas from the black community for the federal government to charge the police officers involved in the death of Jonny Gammage, the department decided not to prosecute.
The FBI will probe the Wilkinsburg shootings in conjunction with local police, Crowley said, but will not take over from county authorities.
A federal prosecution of Taylor under the hate crimes statute would differ from the state homicide case in that it would require the introduction of detailed evidence of racial animus to prove motivation.
But a conviction could carry the death penalty.