TUCSON — The lead detective of a Border Patrol agent’s murder case testified Thursday how she investigated the shooting, but she came under criticism from the defense for doing a poor job.

Tyrone Mitchell, a prosecuting attorney, questioned Ursula Ritchie, a detective with the Cochise County Sheriff’s Office. She was one of four witnesses to take the stand, with the others being the medical examiner, a computer forensics expert and one of the victim’s brothers.

Ritchie said she arrived at the scene of the fatal Jan. 12, 2007, shooting involving Border Patrol Agent Nicholas Corbett just before 5 p.m. She said she spent a considerable amount of time searching for the spent shell casing at the site just north of the U.S.-Mexico border east of Naco where illegal immigrant Francisco Dominguez-Rivera was shot.

Based on her understanding of where the bullet was fired and the direction that the casing was ejected from the gun, she started looking in the area to the front of the vehicle. Then Border Patrol officials told her the shooting actually took place in another location, so she looked near the rear of the vehicle. The casing was later found near the victim’s body.

She said that after the body was removed, she collected items such as clothing and backpacks.

During cross-examination, Jim Calle, a defense attorney, criticized Ritchie for failing to collect some evidence, including gloves that were worn by the victim and the rock the victim may have been holding. Defense attorneys claim their client came around his vehicle and was confronted “face-to-face” by the victim, who attempted to hit him with a rock shortly after 3 p.m. So, the defendant killed him.

Ritchie testified that she did not know the victim was wearing gloves at the time of the incident because the gloves had been removed from his hands before she arrived. She said she collected some gloves but returned them to the family. The defense team found a pair of gloves at the scene last month. The prosecution has agreed to stipulate that the recently-discovered gloves belonged to the victim.

Ritchie testified there were many rocks in the area and she did not collect any because she did not know which one the victim may have been holding.

Ritchie said she was aware there were witnesses of the shooting, but they were not present upon her arrival at the scene. She said they were taken to the Border Patrol station in Naco. Calle also criticized Ritchie for not calling to make sure the witnesses were not being held in the same room. She acknowledged it is important to separate witnesses before interviewing them. But she said she thought Border Patrol officials would have separated them.

Guery Flores, the medical examiner for Cochise County, testified the bullet entered in the left underarm area, passed through some internal organs and came to a rest in the right side of the body near the belly button.

Flores said the shape of a bullet’s entrance wound indicates where the gun was located in relation to the surface of the skin. If the hole is round, it means the gun was held perpendicular to the target. But, as was the case with Dominguez-Rivera’s body, if the wound is oval, then the bullet was fired from an angle.

Corbett is charged with second-degree murder, manslaughter and negligent homicide for fatally shooting Dominguez-Rivera.

The prosecution also questioned Rene Dominguez-Rivera, one of the victim’s brothers. He testified that Corbett hit his brother in the head before shooting him.

Also, the defense cross-examined another one of the victim’s brothers, Jorge Dominguez-Rivera. He testified that he saw Corbett strike the victim in the neck area with his hand as he was holding the gun.

During cross-examination, Flores said he examined the back of the head and neck but did not notice any injuries there. He also said he does not recall being told to examine the victim’s hands, although he did look at them for the presence of any wounds or marks. And he said he does not think the hands were bagged prior to the autopsy.

The  incident  was  filmed by a surveillance video camera. Patrick Smith, who works in the computer forensics unit with the Arizona Department of Public Safety, played for the jury an enhanced portion of video.

The footage shows a vehicle driving, turning and stopping. Someone gets out of the driver’s side door and approaches some people. But the image is rather grainy, making it hard to see exactly what happened.