Detective Glass is a detective from Oklahoma City, Oklahoma.
Castiel, Sam, and Dean Winchester all went to Oklahoma City to investigate the odd death of Gary Freleng. They first met Detective Glass when they went to the morgue to examine Gary's body. She told them that most people thought Gary died of drugs. She didn't believe drugs were the cause.
Sam asked her who called the incident in and she told them it was a friend of Gary's called Olivia Kopple. She then left to answer a call and gave them everything the police had on the case. Dean gave her a card to contact them in case she saw anything weird.
Detective Glass contacts them a while later when a man named Madoff dies. She says that according to witnesses, he stepped off a building and floated in midair, only falling after he looked down. Detective Glass tells them it was a suicide, but points out that both deaths seem to be straight out of cartoons.
They meet Detective Glass again at a bank, where a security guard has been killed, crushed by a 1-ton anvil. Detective Glass tells them that the culprit is a thief they've been calling "Black Hole" because of the black holes he paints on the walls. Sam asks her for files on the thief and Sam leaves with her to get the "Black Hole" files, and Dean and Castiel stay behind.