(ABC News)

A man says his brother, who is accused of killing a 19-year-old girl from Bethany, Okla., worked as an elementary school teacher before selling drugs.

Luis Ruiz, who was arrested Thursday, is accused of murdering 19-year-old Carina Saunders, whose dismembered body was found in a duffel bag behind a grocery store in Bethany, Okla., in October 2011.

Twenty-year-old Jorge Ruiz says his brother, Luis Ruiz, 37, used to teach at Columbus Enterprise Elementary in southwest Oklahoma City.

"I'm not sure which grade he taught," said Jorge Ruiz, according to ABC News affiliate KOCO. "This was a long time ago. I was in like, fifth grade.

"It's pretty crazy; It's kind of shocking. I feel sad. I want to believe that he didn't do it. I still think he's innocent, in my eyes," Jorge Ruiz said.

"I feel bad for the parents of (Carina Saunders)," he added. "They're going through a lot."

Luis Ruiz has been arrested several times for drug-related charges.

In 2010, Luis Ruiz was arrested for having possession of cocaine with the intent to distribute, court documents confirmed.

"He's been kind of a drifter," Jorge Ruiz said, according to KOCO. "He just comes and goes. My whole family hasn't seen him in a while. He's been a drifter and a loner. He has a drug problem and definitely got mixed up with the wrong crowd selling drugs."

According to News 9, police believe Ruiz allegedly murdered Saunders, possibly to scare witnesses so they would cooperate with a drug and human trafficking ring Ruiz was allegedly involved in.

ABC News affiliate KOCO contributed to this report.