The murder of Ronald Kirby, the director of transportation planning at the Metropolitan Washington Council of Governments, could be linked to two other killings in Alexandria, the Alexandria Police Department said today. Kirby, 69, was killed at his home Nov. 11.

Ruthanne Lodato, a local music teacher, was slain in February when a gunman knocked on her door and opened fire, killing her and injuring another women. Her case drew comparisons to the 10-year-old killing of Nancy Dunning, a sheriff’s wife who was also shot to death at her home.

Alexandria Police Chief Earl Cook said at a press conference this afternoon that forensics show the bullets recovered from crime scenes come from the “same general rifling class,” though they could not prove they came from the same weapon.

“The cases appear to be linked, but until we have evidence to point to only one suspect, we investigate all possibilities,” he said.

After the Lodato killing, police described the suspect as a white, balding, middle-aged men with a beard. They still have not established a motive and Cook said residents should not assume that the shooter lives in Alexandria.

Cook warned the public to be cautious and to not open their doors for strangers.

Photo from the U.S. Department of Transportation website