Allison Moore, 22, and two teenage boys were being held in Hamilton County, Ohio, pending extradition to Indiana. All are from Colerain Township, near Cincinnati.
Moore faces charges of murder, burglary and conspiracy to commit burglary. Ripley County Prosecutor Rick Hertel said he wants the juveniles tried as adults.
It wasn't immediately clear if the suspects had attorneys.
Hertel said Monday that he believes Hershman was shot while reaching for the gun during a burglary attempt.
"I believe there was a confrontation shortly after (Hershman's) door was kicked in. There was a struggle for the gun, and she was shot during that struggle," he told Indianapolis news channel WRTV.
Investigators linked one of the juvenile suspects to Hershman, stating the teenager's father is a contractor who worked on Hershman's home, according to a probable cause affidavit.
The document said detectives also connected the suspects to a Ripley County burglary committed on Dec. 29, the day before Hershman was killed.
Hershman was a school bus driver for Milan Community Schools for 25 years, Cincinnati television station WCPO reported. She had also worked as an aide for the schools' special education department.
"It bothers me that a monster took my mother," Dawn Evans, Hershman's daughter, told WRTV. "It would be a different story if it was an accident or a car accident or she died from an illness, but somebody chose to do this."
The shooting has rattled many in the small community.
"I think people in Ripley County think we're this sleepy little community, which to a large degree we are. I think that's why a lot of people live here," Hertel said. "It probably sent shivers down the spines of people who live in this area."