On Friday morning, testimony is expected in a preliminary hearing for Chauncey Lee Daniels, the man accused of opening fire on a MARTA train earlier this month, killing a man and injuring three people.

So far authorities haven’t released a hint of a motive in the death of Zachariah Hunnicutt, the 38-year-old father who died on the train pulling into the West Lake station.

But that could change during the hearing for Daniels, 37, who is charged with murder. In such hearings a detective typically testifies on the evidence against the suspect and a judge decides whether there is probable cause for the prosecution to continue.

MARTA officials have called the April 13 shooting "targeted" and an "isolated" case but declined to say why Hunnicutt would be a target.

Ominously, Hunnicutt posted a video to his Facebook page two days before his death, unleashing a tirade about a woman he claims was trying to “assassinate” his character. He’s standing at a MARTA station in the footage.

“Now you want to shoot at somebody,” he says.

MARTA declined to comment on whether it could be related to the shooting.

Family also told Atlanta media Hunnicutt and Daniels worked together and previously fought.

The shooting came at a time when MARTA is experiencing increased ridership following the I-85 bridge collapse. It also followed four other murder cases worked this fiscal year by MARTA police, an unusual amount of such cases considering the system went four years with none.

Still, MARTA touts a 27 percent overall decrease in crime and notes that arrests were quickly made in each homicide. At least several of the cases were aided by the extensive security system that has gone into place in the last few years on MARTA.

“The safety of our passengers continues to be our No. 1 priority,” MARTA Police Chief Wanda Dunham said in a news release after Hunnicutt’s death.

Additional coverage of the recent MARTA shooting:

Police have charged the suspect with killing one passenger and injuring three others.