She is 72 years old, a widow, and she was alone, as usual, late last Thursday night when two men forced their way into her house on North Edison Street, a quiet residential neighborhood in north Arlington. She had seem them earlier in the afternoon in her backyard and nervously had called a neighbor, but not the police.

The intruders beat her about the face so severely that her eyes were swollen shut. They dragged her through the house, breaking her collar bone and arm, and sexually attacked her.

They destroyed everything -- mirrors were broken, the refrigerator was ransacked, the baby crib mattress she kept in readiness for her infant grandchildren's visit was ripped to shreds.

They heaped the debris on top of her and left her for dead. She lay there 12 hours before she was discovered.

When police saw the carnage, they immediately linked it with a similar incident that occurred three months ago in the same neighborhood. On Nov. 14, two men came to the door of an 83-year-old woman who lived near 24th and Buchanan streets and told her they were delivering a package from the post office.

She refused them entry, but half an hour later, her curiosity got the better of her and she opened her door. She was jumped by two men who forced their way inside her house. While one man searched the house, the other tried to rape her. She fought off the sexual attack, but her shoulder was broken in the process.

After the second attack, four Arlington detectives began to work around-the-clock. "These are . . . real animals and they have got to be stopped," said detective Kenny Adams.

On Wednesday night, police arrested Robert Lee Harris Jr., 20, of 2300 Culpepper St. and two 16-year-olds who live in the same area, just north of the women's homes.

Police and Arlington prosecutor Henry Hudson refused to comment on why the three were arrested. All were charged with buglary, robbery, and felonious assault. Other charges are expected to follow soon, police said.

The two 16-year-olds were being held without bond and Harris in lieu of $100,000.

Crimes of such brutality are unheard of in this neighborhood of modest, well-tended homes that nestle around Arlington Hospital, neighbors say. Residents say they are frightened, their fears only partially allayed by the three arrests.

"I'm retired military," said one neighbor who asked not to be identified. "I was in World War II and I was in Korea and I've never had anything shake me like this.

"My wife is just a basket case," he said.

He said he is thinking of moving and expects that other neighbors will follow suit. "There are five widows that live in this neighborhood," the neighbor said. "I can't imagine that any of them feel very comfortable here right now."

Before the arrests, the detectives had said the assailants may have been looking for money to support drug habits, although they could not explain why the attacks were so vicious.

"We are talking here about vulnerable, elderly people," said detective Adams. "But this was just the worst I've ever seen. They didn't have to go through all of this to get it [what they wanted]."

Some neighbors yesterday questioned how the women would be able to survive such attacks emotionally once they have recovered physically.

The 83-year-old woman attacked in November has left the hospital and now is living with relatives. The woman attacked last week was listed yesterday in "serious" condition in Arlington Hospital.

"It was all so brutal . . . I just don't know how she'd feel about living in her house again after what happened," said Cynthia Garn, a neighbor who lives across the street from last week's victim.

"It will be very hard for her. It is very hard all the way around," Garn said.