An Arlington man was shot to death early yesterday when he went to the aid of a woman who was struggling with a man trying to break into her house, police said.

Guy Allen Melton, a 28-year-old Metro transit worker and student at Northern Virginia Community College, was killed about 2:20 a.m. when the intruder interrupted a party in an Arlington Heights home, according to police.

Melton, a subway mechanic who was studying to become an engineer, was coming to the aid of Aimee Hill when, police said, the intruder pulled out a small revolver and fired one shot into Melton's chest. He was dead on arrival at Arlington Hospital.

The man who shot Melton struck Hill in the face, but her injuries were not serious, police officials said. Another couple in the house at the time was not injured, police said.

Arlington police said yesterday they have no motive or suspects in the shooting which startled residents of the Arlington neighboorhood. The man fled after the shooting without saying anything or taking anything from the house at 824 S. Irving St.

Three detectives canvassed the neighborhood yesterday, trying to find anyone who may have heard or seen what happened. Police also released a composite sketch of the man wanted in connection with the shooting.

The suspect was described as a white male, 30 to 35 years of age, 5'8" to 5'10" tall, medium-build, with brown hair parted on the right side and a mustache. At the time of the shooting, he was wearing gold-rimmed glasses and a light blue sweater or jacket, police said.

"We're amazed that it happened -- and that it happened here," said one elderly man who has lived in the neighboorhood of two-story detached and semi-detached brick homes for more than 30 years. "Nothing like this has ever happened here."

"It's sad," said Phil Pilegraw, who lives across the street from Hill. "I was surprised when I heard about it (the shooting) . . . This is a real quiet neighborhood."

Mark Melton, the victim's younger brother, said his brother was well-liked.

"He didn't have any enemies. He was very outgoing. Everyone liked him."

After Guy Melton graduated from Jeb Stuart High School in Falls Church, he joined the Navy, where he worked as a communications technician. Three years ago, he left the Navy after serving six years.

"He wanted to be an engineer," said Mark Melton. His brother, who lived at 4600 S. Four Mile Run Dr., was in his second year at Northern Virginia Community College in Annandale.