On Saturday, Officer John Cook responded to a call from a friend of Morgan's who wanted him removed from her house. Cook said Morgan was on the porch holding a knife.
He says Morgan refused to drop the knife and lunged at him. Cook said he fired a single gunshot at Morgan, hitting him in the chest.
Family members say Morgan was a stroke victim and disabled.
Rhonda Chalfant of the NAACP in Sedalia says Morgan may have died as a result of excessive force.
"If he had to shoot, I really think he should have just backed away, but if he had to shoot, he certainly should have not shot to kill," she said.
Longtime Sedalia resident Richard Thomas wants answers.
"The question's come up, why wasn't a taser used?" he said. "Could he have backed away, went back to his patrol car, waited for back-up, could he shot him in the leg, shot him in the hand, but not being in the situation, who knows."
Police Commander David Woolery says cook acted appropriately, and did what he had to do to stop Morgan.
"We shoot to stop," he said. "You cannot guarantee that if you shoot a hand, that ya know it's going to stop, or, even make that shot. We train, officer Cook followed training and we shoot until the threat has stopped. He fired one round, that stopped the threat, and that stopped the incident."
Chalfant and others still want an investigation.
"Once again, civil rights are civil rights and if anyone's rights are violated, we are all at risk," she said.
The Missouri State Highway patrol is handling the investigation.