Alexandria, Virginia (CNN) -- The shooting death of a music teacher last week has investigators asking whether the crime is connected to two other unsolved killings in Alexandria, Virginia.
Ruthanne Lodato, 59, was shot to death when she answered a knock on her front door Thursday morning. Her elderly mother's caretaker was wounded, but survived, police said.
"This is a very stable community of people who know one another, and crime of this sort is unfathomable," neighbor Barry Mudd said.
The crime scene is in a quiet residential neighborhood, just a mile from the home where Ronald Kirby, a prominent transportation official, was shot and killed in November. The 69-year-old man's slaying is still unsolved.
Detectives, including from the FBI and Alexandria Police Department, are looking for possible connections between the Ladato and Kirby killings, as well as to the unsolved shooting death of Nancy Dunning, the wife of a former sheriff, just two miles away in 2003, police said.
Although the crimes are spread over a decade, they share similarities. They happened within two miles of each other in the Washington suburb. All three victims were gunned down in their homes with no signs of a forced entry.
"You can't help but think that, but hopefully it's not multiple people," Alexandria Mayor William D. Euille said.
Police released a sketch of a man they suspect might be Lodato's killer, hoping to generate tips from the community.
"Don't be afraid to call it in, because you just never know," Euille said at a news conference.