The DeKalb County elementary school teacher taken out of his school in handcuffs Friday was one of 10 men charged in connection with a 2016 Clayton County killing of two children, according to an indictment filed Wednesday.

Speaking at Clayton County Police Department headquarters Thursday morning, Chief Kevin Roberts said the nearly 18-month investigation included more than 50 interviews with people in metro Atlanta and Tennessee. He was elated about the progress toward serving justice for the family of the brother and sister shot to death on Oct. 22, 2016.

"That indictment serves as notice to criminals — and more specifically gang members who commit crimes in Clayton County — that they will be apprehended and prosecuted to the greatest extent," he said. "Today is a good day."

Charged in the killings are: Vernon Jerome Beamon, 29, of Decatur; Jamon Marqice Bynum, 27, of Atlanta; Melvin Allen Crockett, 34, of Forest Park; Devin Dunson, 27, of Decatur; Deundre Demond Mitchell, 18, of Chattanooga, Tenn.; Jamar Rashaad Mitchell, 24, of Decatur; Sterlin Obche Pate, 23, of Decatur; Christopher Leonard Spencer, 28, of Decatur; Sherman Thomas, 24, of Covington; and Michael De’Sean White, 26, of Stone Mountain.

Eight of them are charged with murder. Other charges include aggravated assault, third-degree child cruelty, home invasion, felony firearm possession, violating the Street and Gang Terrorism and Prevention Act and violating the Racketeer Influenced and Corrupt Organizations Act.

Another person who police believe was not connected to the deaths faces a weapon charge.

Police said 11-year-old Tatiyana Coates and her brother, 15-year-old Daveon Coates, were sleeping in a Clayton County home when they were shot to death by gang members who may have been after someone else: Deundre Mitchell, who they suspected of taking weapons from a DeKalb County apartment. Deundre Mitchell has been charged with murder in the case.

Roberts said it still is not clear whether the children were targeted.

“They likely thought Deundre was one of the children in the bed,” he said. “But (Tatiyana and Daveon) could not have known the harm that was coming their way.”

Four younger children were in the home at the time of the shooting. None was hurt.

Roberts said the Coates family sees the indictments as progress, adding that his department has been in constant contact with them over the past 18 months.

“There is some small piece of solace that they’ve received from the progress of the case so far,” he said.

All men charged are believed to be members of the Crips gang. They will be investigated to see whether they had roles in other gang-related crimes, Roberts said.

At least one of the suspects already has been tied to three homicides in surrounding counties.

Clayton County Police Department Detective Stefan Schindler said the case crossed state lines after a weapon dropped during a drive-by shooting in Chattanooga the day after the killings was linked to the homicides.

He declined to go into specific details, citing the continuing investigation.

Still unknown is what role the teacher, White, played in the crime.

Hired by DeKalb County School District in March 2017 as a paraprofessional and as a teacher ahead of the new school year, he passed two background checks, district officials said. Georgia Professional Standards Commission records show White received a clearance certificate, which shows he cleared a fingerprint and criminal background check. No other criminal charges against White were found during a cursory public records search.

He was arrested and led out of Decatur’s Toney Elementary School Friday in handcuffs. District officials have said White was removed from his position until the police investigation is complete.

“We were absolutely flabbergasted to come to the realization that we had a fifth-grade teacher in a public school teaching children, to be part of this,” Schindler said. “That took our breath away.”