Serial Killer Feared After Virginia Shooting Investigators in Alexandria probe link between three shootings.

Feb. 10, 2014 -- Police in Alexandria, Va., have launched a manhunt for a balding gunman with a white beard amid fears that a serial killer may be on the loose.

Two people have been murdered inside their homes in recent months with no sign of forced entry. The shootings bear similarities to a decade-old unsolved murder.

The most recent shooting came Thursday when Ruthanne Lodato, 59, was shot and killed after a knock at her door around 11:30 a.m. A caregiver was also shot, but survived.

Investigators believe an older man with a white beard was the gunman, pulling out a gun and firing repeatedly when the door opened. Police have released a sketch of the suspect. The man is described as balding with some gray hair, a beard and wearing a tan jacket.

Resident Daniel Bender told ABC News that the shooting has had a profound impact on the region.

“It touches us all whether you knew her directly or not,” he said. “It ripples out. You can't help but be affected by it.”

Ellen Epstein, who owns a dog-walking company, said the neighborhood is usually quiet and calm.

"Everybody's conjecturing a million things," she told ABC News. "It's really hard to believe that in a neighborhood like this, nobody saw the perpetrator. That's what's really strange."

Some of the neighborhood fear involves the shooting’s similarity to previous crimes. In November, Ron Kirby, a transportation official, was gunned down in his home.

Nancy Dunning, a real estate agent, was also shot and killed inside her home in 2003.

All of the shootings happened within two miles of each other, during the late morning or early afternoon with no forced entry.

While police are looking for connections between the crimes, Alexandria Mayor William Euille wants the investigation to unfold before making any judgment.

“Residents have a right to be concerned, but I don’t want to characterize it that there is a serial killer floating around this city,” Euille said.

Following Thursday’s shooting, residents have been calling locksmiths, hoping to get peep-holes installed in their doors, police said.

Bender said the recent shooting has made area residents more vigilant.

"I don't know that people are more fearful, but I think they're more skeptical. I think they're more cautious," he told ABC News.

Former FBI agent Brad Garrett, an ABC News consultant, said residents should be cautious, making sure they have a way to check the front door without answering, using a side window or other means to check on visitors.

He also wondered if the victims share anything in common, such as a church or social organization.

Garrett said it's possible the same person is responsible for all three murders.

“When you’re dealing with somebody, if this is one person, this is a very troubled person. And they can go dormant for a while before they reactivate,” Garrett said.

“So is it conceivable that one guy did all three of these? And the answer is yes.”

ABC News' Dan Good and ABC News Radio contributed to this report.