A person of interest has been identified in the fatal shooting of a Marine Corps veteran during a robbery at the Lancaster gas station-convenience store he worked, authorities said this week.

Detectives would like to speak with Deonta Darrell Johnson “about this investigation and are asking (for) the public’s assistance to locate him,’’ Deputy Lillian Peck of the Sheriff’s Information Bureau said.

Johnson is described as Black, 21 years old, 5 feet 11 inches tall and 220 pounds. He has brown eyes and black hair, a tattoo on his neck and frequents the East Lancaster and Los Angeles areas.

A teenage boy has been arrested and charged in connection with the case and a second suspect is being sought, Peck said.

Two reward offers totaling $30,000 were offered in March for information leading to the arrest and/or conviction of the suspects responsible John Ruh’s killing. The Los Angeles County Board of Supervisors offered $20,000 and the city of Lancaster added another $10,000.

Ruh, 61, of Lancaster was working a cashier shift when the business in the 44400 block of Division Street was robbed about 8:30 a.m. Feb. 19 by two male suspects, one of whom shot him in the chest before both fled on foot, according to the Los Angeles County Sheriff’s Department.

“This has left our family totally devastated …,’’ Ruh’s girlfriend Michelle Brace said at the time the rewards were offered. “He was a good man, and all we want is for him to have justice.’’

Ruh’s sister, Teresa Vail, said “nobody deserved to die the way he did.’’

Anyone with information about the case or Johnson’s whereabouts was urged to call Sheriff’s Homicide Bureau Detectives Steve Blagg or Scott Lawler at (323) 890-5500.

Anonymous tips can be submitted through Crime Stoppers by calling (800) 222-TIPS or sending an email to lacrimestoppers.org.