CHARLESTON, S.C. — A state crime scene investigator testified Tuesday that he was concerned when he examined the body of a black motorist shot by a white police officer because what he saw didn't jibe with what he was told about how Walter Scott died.

Scott's wounds "seemed to be in the back and side and didn't seem to be correct," Almon Brown testified during the murder trial of Michael Slager.

Brown, who was an investigator for the State Law Enforcement Division at the time, testified that when he arrived at the scene of the April 2015 shooting, he was briefed that it happened during a confrontation between Scott and Slager, a former North Charleston patrolman.

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Slager is standing trial for murder and could be sentenced to 30 years to life if convicted. Scott was shot as he fled a traffic stop after being pulled over for having a broken taillight on his car. A video made by a bystander showing Slager shooting Scott in the back stunned the nation.

Brown was called as the prosecution presented witnesses for a fourth day in the trial. Photos he took at the crime scene, including a photo of Scott's body, were introduced and shown to the jury.

Former North Charleston Police Officer Michael Slager sits at the defense table during testimony in Slager's murder trial, Tuesday Nov. 8, 2016, in Charleston, South Carolina. Grace Beahm/Pool / Getty Images

Related: Walter Scott's Mom Collapses During Cop's Murder Trial

Brown was one of three crime-scene investigators who testified Tuesday. Also testifying was former North Charleston Police Department investigator Scott Wyant, who said he didn't do a complete investigation at the scene because state investigators handle shootings involving police officers.

Wyant served more than 20 years with the department. He said on cross-examination that he was told by his superiors in the department not to do a trace-evidence investigation on Slager looking for such things as gunpowder residue. Wyant said he had expressed his concern that doing so would be a conflict of interest.

Defense attorney Andy Savage has long questioned the adequacy of law enforcement's investigation and at one point last year filed a motion asking the court to look into what he contended was the state's destruction of evidence.

Meanwhile, city officials have said that local police and the FBI are investigating nine suspicious letters mentioning racially oriented violence that were sent from outside of the United States to hotels and a black church where nine parishioners were gunned down last year. The letters arrived amid both the Slager trial and another trial with racial overtones that is taking place in federal court across the street.

Related: Nearly All-White Jury Seated in Trial of Ex-Cop Who Shot Unarmed Black Man

Jury selection resumes Wednesday in federal court in the trial of Dylann Roof, who is charged with hate crimes, obstruction of religion and other counts in the fatal shooting of nine black parishioners at the Emanuel AME Church in June 2015.