Washington-area police said they had linked the two suspects in the recent sniper shootings to another strike in suburban Silver Spring, Maryland, on September 14th, almost three weeks before the shooting spree started.
A 22-year-old man was shot in front of a liquor store in Silver Spring, the center of the rash of killings, survived the assault and is recuperating, police said in a statement.
"The task force has officially linked this shooting to the other sniper shootings in the area," the Montgomery County, Maryland, police department said in a statement.
This takes to 14 the number of sniper victims in the Washington area, including 10 killed and four wounded.
The two sniper suspects - John Allen Muhammad, a 41-year-old Gulf war veteran, and John Lee Malvo, a 17-year-old Jamaican - have also been charged for murders in Alabama and Louisiana.
Police are expanding their investigation to include other states after finding that the rifle used in the Washington-area sniper slayings was the same weapon used to kill a woman during a robbery at an Alabama liquor store on September 21st, Alabama authorities said on Friday.
Authorities are also searching for possible links to shootings in the states of Washington, Oregon, California, Arizona, Tennessee and Michigan.