Evidence that was collected as part of the investigation into the death of a Donna teen was presented to jurors on Tuesday.

Carlos Contreras, 23, is on trial charged with the death of Genaro Isaiah "Izzy" Castillo, whose body was found near Donna Lake on Jan. 12, 2020.

Castillo was 18-years-old when he died.

Through the investigation, authorities learned Castillo and Contreras were arguing over money linked to criminal activity when the shooting happened.

On Friday, a judge declared a mistrial in the murder case after the defense said prosecutors offered immunity to a witness without letting them know. The trial restarted on Monday.

PREVIOUS STORY: Family of slain Donna High School student speaks out after mistrial declared

Among the witnesses was 25-year-old Jacob Villalon, a mutual friend of the suspect and victim. Villalon testified that Contreras had asked him to find him a gun because "he thought guns were cool.”

Contreras never told him what his intentions were for the gun, Villalon testified, 

Villalon said at around 2 a.m. on the day of the murder, Contreras called him asking him to go to Donna Lake to help him pull his truck out of the mud. Villalon said he didn’t go. He later learned Castillo was found dead.

A specialist testified that bullets, a handgun and a magazine were found on the property where Contreras lived, but not in the main residence. 

Shoes with brown stains and clothes taken from Contreras’ room were also shown, but jurors learned they were not swabbed for DNA. 

Crime scene specialist Sandra Rangel said she tested for gun residue on three handguns and on the body of Castillo, but his clothing was not tested for gun residue. 

The state also called a handwriting expert who analyzed a letter allegedly written by Contreras that was found in his room.

The letter was shown to jurors and said, “one day I’ll do something bad. I love you mom and dad.”  The expert found the handwriting was similar to Contreras’ but could not say for sure because more handwriting samples were needed.

Testimony will continue Wednesday morning.