According to court documents and police reports, 20-year-old Andrea Nunez, who was fatally shot early Sunday morning in Kennewick was almost 5 months pregnant.

17-year-old Adrian Mendoza appeared in Benton County Superior Court Wednesday and plead not guilty to First Degree Murder. He has been charged as an adult for his role in the crime. Another 17-year-old whose name has not been released is facing possible 2nd Degree charges, he was taken into custody at Southridge High School earlier this week. It is yet to be determined if he will also face adult charges.

Police say Nunez and her boyfriend were walking near 7th and Gum around 4:20am Sunday when they reportedly heard someone yell "westside," which is a gang reference. Nunez reportedly yelled back "southside", which indicates a rival gang. The police report says she was shot in the back, the bullet passed through her heart and out the other side of her chest. She was found lying in the road, and pronounced dead at the scene. Mendoza was one of two suspects captured near the scene on multiple surveillance cameras, that's how officers were able to ID him and the other suspect and locate them.

Police found a cellphone lying in the street not far from the crime scene, it had apparently been dropped. The phone had the same number used by Mendoza to contact his parole officer, and it had been paid for by his mother's boyfriend, Robert Agli. Mendoza's mother has been arrested for rendering criminal assistance. It is believed the phone belonged to the shooting suspect.

The phone's wallpaper backround contained the words "westside" and "18th" which police say are references to area street gangs.

A third suspect is still on the loose, 22-year-old Ezekiel Sanchez of Kennewick. Police have not specified what role he is thought to have played in the murder. No other suspects are being sought at this time.