FERGUSON, Mo. — The police chief of the St. Louis suburb that has been rocked by racial unrest since a white police officer shot an unarmed black teenager to death said Wednesday that he won’t be pressured into publicly identifying the officer despite mounting demands from clergy, protesters and even hackers.

Ferguson Police Chief Thomas Jackson, who has been the public face of the city torn by Saturday’s death of 18-year-old Michael Brown, told reporters the St. Louis County investigation of the shooting could take weeks. In the meantime, he said, his department welcomes Justice Department training on racial relations in the suburb, where two-thirds of the 21,000 residents are black while all but three of the police force’s 53 officers are white.

“Unfortunately, an undertow (of racial unrest) has bubbled to the surface,” said Jackson. “Race relations is the top priority right now.”

The mystery of the officer’s identity has fanned the discord, with Jackson arguing that revealing that detail could bring retribution to the officer whose life has been threatened since Saturday.

But civil rights activists and the attorney for Brown’s family, all pressing for calm amid nights of unrest since Brown’s death, counter that knowing the officer’s name may help the area to heal, allowing the National Association for the Advancement of Colored People and others to dig into the officer’s background for any prior brutality.

“We don’t want anyone’s life threatened. If someone like this officer is killed, then there is no justice,” said John Gaskin III of St. Louis County’s NAACP chapter.

Police have said the shooting happened after an officer encountered Brown and another man on the street. They say one of the men pushed the officer into his squad car, then assaulted him in the vehicle and struggled with the officer over the officer’s weapon. At least one shot was fired in the car. The struggle then spilled onto the street, where Brown was shot multiple times.

Dorian Johnson, who says he was with Brown when the shooting happened, has told a much different story. He has told media outlets that the officer ordered them out of the street, then tried to open his door so close to the men that it “ricocheted” back, apparently upsetting the officer. Johnson says the officer grabbed his friend’s neck, then tried to pull him into the car before brandishing his weapon and firing. He says Brown started to run and the officer pursued him, firing multiple times. Johnson and another witness both say Brown was on the street with his hands raised when the officer fired at him repeatedly.

Robert McCulloch, the county’s prosecutor, said that investigators were interviewing Johnson on Wednesday.

Jackson said that the officer sustained swelling facial injuries during the confrontation that preceded the shooting.

Brown’s body remained on the street for hours – a span Jackson deemed “uncomfortable” but justified, given that “you only get one chance at that crime scene” to process it correctly. Jackson said authorities also were concerned about gunfire they could hear from a nearby building.

In the shooting’s aftermath, the notorious hacking collective Anonymous has taken credit for hacking into the city website and shutting it down for much of Monday. The group also released what it said were audio experts from St. Louis County dispatch on the day Brown was killed. Police declined to comment on the recordings.

On Tuesday, hackers posted pictures of St. Louis County Police Chief Jon Belmar’s home and family online, as well as his home address and telephone number in hopes of pressuring him to release the officer’s name.

“Realistically, what positive could come from that information coming out?” Jackson said. “Right now, people want it so they can destroy that person’s life. That’s the only reason that group’s asking for it.”

But community members said they want to know who the officer is.

“We have the right to know, and the family has the right to know who murdered their son,” said Sahari Gutierrez, a 27-year-old legal assistant.

Two reporters covering the shooting and unrest say they were arrested at a McDonald’s Wednesday evening in Ferguson’s commercial corridor.

Wesley Lowery of The Washington Post and Ryan Reilly of The Huffington Post say they were working in the fast-food restaurant when SWAT officers came in to quickly clear the area. Both quickly tweeted about their arrests, detention and subsequent release without any charges.

Police Chief Jackson did not immediately return a cellphone message from The Associated Press seeking comment.