PITTSBURGH (KDKA) - It's been nearly two days since Officer Calvin Hall died at UPMC Presbyterian hospital.
Police now have one person of interest in custody being questioned about the shooting.
Police call Christian Bey a "person of interest," and we're told he's being questioned about the shooting of Officer Hall.
A career criminal, Bey has a trail of drug and weapons arrests stretching back more than a decade.
Most notably, he was sentenced to 3 to 6 years in state prison for his involvement in a multi-state drug ring, allegedly trafficking in crack and cocaine.
He fled a corrections facility in 2013 and was arrested again three years ago for fleeing police, reckless endangerment and DUI.
WATCH: Meghan Schiller's investigation of Christian Bey
Still, on parole, police have detained him on another violation while they interrogate him in relation to the Officer Hall murder.
KDKA learned Bey is from Homewood and his address is reported along Monticello Street in the same block where shots rang out early Sunday morning.
Police have not charged Bey with a crime, and KDKA was told he's being held for unrelated charges.
Today, Bey's family expressed regret but asked for a fair investigation.
"We just want to allow Mr. Hall's family to put him to rest and we're sorry for what happened and we're just waiting on the investigation," Sam Gibson, Bey's uncle, told KDKA.
WATCH: KDKA's Meghan Schiller report live
KDKA's sources tell us he turned himself in for a parole violation.
He most recently pleaded guilty to DUI, eluding a police officer and recklessly endangering another person back in 2015.
The judge sentenced him to jail time and put him on probation for several years.
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Police say Officer Hall was unarmed and off-duty at the time of the shooting.
Someone opened fire and shot him at close range three times in the back, reportedly as he was trying to break up a fight.
Chief Scott Schubert said there's a lot of evidence that shows he was likely "acting under the color of the law" at the time of the shooting.
Police also said the "net is closing in" on the person who allegedly did this.
Neighbors in the community say they're rooting for the police in terms of them making an arrest and filing charges soon.
This afternoon Maurice Hickman of the Focus Trauma Team walked Monticello in hopes of counseling residents.
"We come out and start the process of healing, that's what we do," he said.
"We just pray for people and try to be a support system for all the residents in the community."
Neighbors say they hope that charges will be filed before Officer Hall is laid to rest this upcoming Tuesday.
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