To the hunt for a possible serial killer just outside Washington, D.C. Police in Alexandria are saying three high-profile murders, one in the last month, may all be linked and ABC's David Kerley is on... See More
To the hunt for a possible serial killer just outside Washington, D.C. Police in Alexandria are saying three high-profile murders, one in the last month, may all be linked and ABC's David Kerley is on the scene with the latest. Reporter: Two killings in the past six months and one ten years ago could all be linked say police with new ballistic reports. The bullets have the same general rifling class and characteristics similar in design for all cases. Reporter: Police can't say definitively they came from the same gun but there are so many other similarities. The piano teacher killed when she opened the door. A local transit official killed at his home and the connection back to the real estate agent, wife of the sheriff, gunned down at home during the day. All three active in the community. All three killings within two miles of each other in Alexandria, Virginia. The connections are chilling for residents. I don't like the fact that there's a serial killer out there. Scary, of course. Reporter: The man they are looking for, white, balding and bearded. Police won't talk about motive but former FBI profiler and ABC news consultant brad Garrett believes he has a grudge with the city. He believes in his mind these three people represent the city of Alexandria and the city has wronged him and he's going to make it right. Reporter: Since the killing of piano teacher Ruthanne Lodato residents have been keeping locksmiths busy installing peepholes and residents do need to be vigilant. If any of you are suspicious of anything, please don't open your door. Call the police. Reporter: Since that piano teacher was killed at that door behind me there have been 500 tips given to police. The FBI is involved but so far just the sketch of the man would could be a serial killer.
This transcript has been automatically generated and may not be 100% accurate.