Marckel Ross was fatally shot Sept. 11, 2012, while walking to Central High School in Capitol Heights. (Ross family)

Prince George’s County police and prosecutors will announce next week that they have made an arrest in the 2012 slaying of an 18-year-old Central High School student who was shot while walking to school, the assistant police chief said Friday.

Appearing on News Channel 8 to discuss youth violence, Prince George’s Assistant Police Chief Kevin Davis said “an arrest is being made” in the slaying of Marckel Ross, and police and prosecutors would announce that arrest early next week. He offered no other details.

John Erzen, a spokesman for Prince George’s State’s Attorney Angela Alsobrooks, said only, “The investigation is ongoing, and we are getting closer to wrapping it up and being able to make an announcement.”

Law enforcement officials, speaking on the condition of anonymity to discuss the ongoing investigation without being disciplined, said police took into custody several people in connection with an unrelated robbery late last year, and recovered the gun they believed was used to kill Ross. Police and prosecutors then began working to identify which of the people might have been involved in Ross’s shooting and which actually pulled the trigger.

The officials said detectives believe they have identified the shooter, though as of Friday, no one had been formally charged.

Ross was shot sometime before 6:50 a.m. Sept. 11, 2012, as he walked alone in the 6100 block of Old Central Avenue on his way Central High School, police have said. The officials said investigators believe the incident might have started as a robbery attempt, and Ross did not know the person who shot him. It is unclear whether anything was taken.

Ross was the second of six Prince George’s students to be slain this school year.