Bach had been reported missing on Thursday. She had been last seen leaving her home in Portage at around 10 p.m. Thursday. Bach's car was found abandoned at about 3:30 a.m. Friday morning at a general store. The driver's-side door was open and some of Bach's belongings were inside.
After a massive search involving hundreds of volunteers, Bach's body was found Saturday near a set of railroad tracks just 300 yards from where McCowan lives in Union Township.
The coroner says that Bach died of a gunshot wound to her neck. Police declined to comment on what motive McCowan could have had to kill Bach. The coroner says there appears to be no evidence of sexual assault.
"The wound that she suffered would've been an instantaneous death," said Harris County Coroner Chuck Harris. "There would have been no suffering.
McCowan was formally charged with one count of murder, and he was being held Monday with no bond at Porter County Jail. According to Porter County Sheriff's Sergeant Larry LaFlower, McCowan's initial court appearance is scheduled for Monday.
Police questioned McCowan Monday. McCowan had been described as an acquaintance of Bach. Police say McCowan was the last person to see Bach alive and is responsible for her death. "They were supposed to hang out... meaning, do what friends do - hang out," said LaFlower. "We're not sure what their activities were gonna be that night."
Authorities say their investigation is ongoing and they are checking to see if any other people may have been involved.
"We're making sure that we're not just honing in on him. Granted, he is in custody right now on suspicion of murder, but we want to make sure that we investigate it thoroughly to make sure anybody that was involved or there when this occurred is brought in," said LaFlower.
McCowan was taken into custody while visiting a friend in Bloomington, Indiana.
People who knew Bach remained in shock Monday about her death.
"It's just upsetting for everybody that is here and praying for her family," said Joshua Sessions, a manager at the restaurant where Bach worked.
Employees at the restaurant where Bach worked for the last year and a half cannot believe she is gone.
"All of us knew her that worked there, and just hearing different things - it's hard," said Amanda Ashford, a friend of the victim.
Both Portage High School, where Bach graduated in 2011, and Wheeler High School, where McCowan attended, had grief counselors on hand Monday. McCowan graduated this spring from Wheeler. His family was at home but declined to comment on the charges Monday night. Neighbors say that investigators were searching the area for much of the day.
"I feel for the family that lost a daughter, and I hope they pin it on him if he done it," said Leo Hinkle, a neighbor of McCowan.
Candles lit a memorial at Portage High School in Bach's memory Monday night. Bach had planned to attend Indiana University Northwest in January.
The Bach family said Monday they were still making funeral arrangements.