The bullet and shell casing recovered from a shooting scene at the Bedrock Bar in October 2016 were consistent with the firearm suspect Aaron Demetrius Humphreys was seen holding shortly before 47-year-old Eric Wayne Burns was killed.

That was the testimony of Minnesota Bureau of Criminal Apprehension forensic scientist Nathaniel Pearlson on Monday in State District Court.

The firearm used to kill Burns at the front door of the former Lincoln Park establishment has never been recovered, but authorities allege that Humphreys photographed himself holding the murder weapon in the bar's bathroom just minutes before killing the victim.

Pearlson, a firearm examiner, said the weapon Humphreys was holding appears to be a Haskell JS-45 semi-automatic pistol. He testified that a spent bullet located on the sidewalk and a shell casing recovered from a garbage bag inside the bar were compatible with the weapon.

Pearlson was one of the final prosecution witnesses to take the stand on the fourth day of testimony in Humphreys' Duluth murder trial. The state rested its case later in the day.

Pearlson told St. Louis County prosecutor Chris Pinkert that he was unable to determine the distance at which the bullet was fired, but said the Haskell firearm could have fired the bullet and that the casing had markings consistent with that family of firearms.

However, under cross-examination from defense attorney Kassius Benson, Pearlson acknowledged that Haskell was one of about 30 major firearm manufacturers that he could not exclude in his analysis of the bullet and casing.

Benson, who contends that Burns was shot from outside from the bar by a man Humphreys knew only by the nickname "Memphis," also questioned the lack of a visible muzzle flash in surveillance video of the incident.

Pearlson said there would have been a flash, but it may not have been visible due to lighting, video quality or obstructions between the firearm and the camera.

"I shoot a lot of firearms in a lot of different scenarios," he testified. "Sometimes you see a muzzle flash, sometimes you don't."

Later in the day, Benson pressed the case's lead investigator about the Duluth Police Department's efforts to research the alternative suspect. "Memphis" first came to light this January - well over a year after the shooting - when the defense alleged him to be the shooter, known only to Humphreys as an acquaintance of his friend, Orin Bernard Vann.

Investigator David Decker testified that he ran the nickname through the department's database. He said he found only one person using that name, and he was in prison at the time. Decker said he later received information from Vann, via an attorney, that he was familiar with four people who used the nickname in the Duluth area.

Decker said a second man using that nickname was identified, but he was last known to be in Duluth in January 2013 and all indications were that he had since returned to the Tennessee city. Decker conceded, however, that he could not definitively determine that man's whereabouts at the time of the shooting.

He added that he was unsuccessful in obtaining an interview with Vann, who is also charged criminally in connection with the case and invoked his Fifth Amendment right not to testify in Humphreys' trial last week.

Decker testified that extensive efforts were undertaken to locate the firearm that was used to kill Burns. He also was asked about the muzzle flash issue.

"Considering all the circumstances - the darkness of the video, the direction the gun would've had to be facing from inside the bar - that didn't sway me from all the other evidence I saw," Decker told jurors.

Investigator Jeanine Pauly, who completed a forensic examination of Humphreys' cellphone, also took the stand for a second time Monday.

She testified that in the hours between the shooting and Humphreys' arrest, he communicated with numerous people, downloaded a police scanner application and searched online for the Duluth Police Department, News Tribune and St. Louis County jail roster.

In a text message to his mother, the defendant allegedly wrote: "Mom, something happened. I'm sorry. I love you."

The prosecution concluded its case by showing body camera video from Humphreys' arrest. As he is being handcuffed and led to a squad car, the suspect could be heard repeatedly shouting comments including, "Just shoot me!" and "Kill me!"

Humphreys is charged with intentional second-degree murder, illegally possessing a firearm and fifth-degree assault.

The defense will have an opportunity to call any witnesses Tuesday, with the jury expected to get the case after hearing closing arguments Wednesday. Sixth Judicial District Judge David Johnson is presiding.