Bach was last seen leaving her home Thursday night, and her car was found in Wheeler, Ind. Friday. Her body was found Saturday afternoon along railroad tracks following a massive search in Northwest Indiana.
Porter County authorities Sunday were holding the 18-year-old male friend of Amanda Bach on suspicion of murder, but he has not yet been charged with a crime. He is the son of a Crown Point Police Department employee. Porter County Sheriff David Lain said he is seeking murder charges against the teenager.
Meanwhile, her family, friends and the community are mourning her death.
"Everyone in Amanda's family loved her very much. Her smile lit up the room whenever she walked in," said family spokesman Dr. Carlos Cespedes, Bach's uncle. "She was too beautiful for this world, and we will all miss her very much."
Bach went missing Thursday night. She was last seen by family members leaving her Portage home around 10 p.m. Thursday to visit the Wheeler home of the male acquaintance now being held by authorities. Residents living near where Amanda was found say they heard noises a few hours later.
"The next-door neighbors, which is in between us and their house, made a report I think Friday morning of hearing the screams, I think they said they heard some at 1:30, and then, my grandpa's dog, of course, was barking," said neighbor Nate Fisher.
Investigators say Bach's body was found Saturday afternoon about 300 yards from the suspect's home, within three miles of the general store in Wheeler where her 2006 gold Pontiac G6 was found abandoned around 3:30 a.m. Friday morning. Police do not know how the vehicle got there.
"The car had a flat tire, the driver's side door was standing open, and Amanda's purse and its contents were inside," said Lain.
Detectives say the suspect was arrested by Indiana University police in Bloomington, where he had been since Friday on a previously-planned trip. He was transported back to Porter County early Sunday morning.
Bach's friends and classmates held a candlelight vigil in her honor Saturday night at Portage High School. The 19-year-old graduated from there last spring, and her relatives say she had planned to attend Indiana University Northwest.
"She was the sweetest girl you could ever know. She was the nicest person in the world and would do anything for anybody, help anybody out," said Eric Driver, a friend of the victim.
"She's a gorgeous girl. Everybody knew her. She was one of those girls if you didn't know her, there was something wrong with you," said Angel Berg, a classmate.
Witnesses say the car had a flat tire, the driver side door was open, and the keys were in the ignition.
"To think that somebody thinks they have the right to take someone's life like that, it's just ignorant. It's not right at all," Driver said.
Investigators would not outline a motive for the crime or give further details about their probe Sunday.
"This investigation is ongoing. There is a significant amount of work yet to be done," said Lain. "We are asking anyone with any knowledge of the events or people related to this crime that took place since last Thursday to please come forward for the sake of Amanda and her family."
On Saturday, Bach's loved ones organized a massive search, and her parents made a heartfelt plea for her safe return. More than 100 volunteers searched on the ground while the sheriff's department helped from helicopters.
"She is the sunshine of my life. She's beautiful. Amanda, please come home if you're out there," said Sandra Bach, the victim's mother.
Those who knew Bach offered condolences to her family.
"My prayers will be with them, and they've got a lot of people in the Portage community. Everybody will be supporting them for sure because she was definitely loved by the community, loved by a lot of people," said Driver.
Police say there was trauma to Amanda's body, but a cause of death will not be announced until an autopsy is performed Monday. Funeral arrangements were pending Sunday night.
While police are seeking murder charges against the suspect, they still ask that anyone with information on the case contact them.