Two Tennessee men have been indicted on first-degree murder charges in the fatal shooting of a civic leader and former airline executive on a Memphis sidewalk, prosecutors said Thursday.

McKinney Wright Jr., 22, and Quandarius Richardson, 18, were also indicted on attempted especially aggravated robbery charges in the death of Philip Trenary, president and CEO of the Greater Memphis Chamber of Commerce. The 64-year-old Oklahoma native was also the former head of Pinnacle Airlines.

Trenary was walking along a street and talking on his cellphone in September when a man exited the passenger side of a pickup truck, approached Trenary from behind and shot him in the head, the Shelby County district attorney's office said. The shooting took place near where the chamber was holding its annual "Move it Memphis" race, near a large apartment complex and not far from historic Beale Street.

Witnesses told police that a white Ford F150 truck left the crime scene. The day after the shooting, police chased a truck matching the witnesses' description. Police said the truck had been stolen.

Richardson was arrested after the truck he was riding in crashed into other vehicles during the chase, injuring several people, police said. Wright and a 16-year-old girl were arrested the following day.

According to statements made by Wright and the 16-year-old, Richardson and Wright discussed possible robbery targets as they drove around downtown Memphis the night Trenary was shot, a police affidavit said.

Richardson also was indicted on charges of theft of property over $10,000 and evading arrest in a motor vehicle, risking injury or death.

Richardson plans to plead not guilty and fight the charges, said his lawyer, Arthur Horne. Wright's attorney did not immediately return a phone message.

The girl's charges were handled in Juvenile Court. The resolution of the case was not disclosed by the district attorney's office because she is a juvenile.

Trenary founded Exec Express Airlines in Stillwater, Oklahoma, in 1984. The company moved to Texas and was renamed Lone Star Airlines in 1987.

He came to Memphis in 1997 to run a regional airline that morphed into Pinnacle, a $1 billion, 7,700-employee regional airline operator.

Trenary oversaw the acquisition and integration of Colgan Air in 2007 and Mesaba Airlines in 2010 before leaving Pinnacle in 2011.

He was named president and CEO of the Greater Memphis Chamber of Commerce in 2014 and guided the launch of the chamber's Chairman's Circle, a group of more than 100 business leaders working to bolster the economy of the Memphis region.