Andrew Adkins was watching television in the living room of his new $15,000 mobile home in Jacksonville, Fla., one afternoon last November when the police came rapping on his door.

They asked if he knew Ray Killian, a man who in 1975 was sentenced by rural Virginia courts to a total of 11 years in prison after being convicted on separate charges of stealing a $500 stereo from the house of his stepbrother and $5 in change from a soft-drink machine in the office of his former employer.

"No, I never heard of the man," the bearded Adkins replied. Adkins lied. He knew Ray Killian, all right. In fact, he had been Ray Killian until June 25, 1979, when he walked away from a road gang at a medium-security prison in Fairfax County.

Now, Killian, 30, is back in a Fairfax jail after having lived almost four years as model citizen Andrew Adkins--until his estranged wife turned him in to police, Killian testified yesterday in a plea hearing before Fairfax Circuit Court Judge J. Bruce Bach.

"I always knew I would have to come back," said Killian, who said he lived a law-abiding but haunted life in South Carolina and Florida. "I'm kinda glad I'm getting it over with now." Killian pleaded guilty yesterday to escape, a charge that carries a one- to five-year prison term. Sentencing is set for April 22.

Killian's case has raised questions among defense attorneys and prosecutors about differences in sentences imposed by downstate Virginia courts vs. those in suburban Northern Virginia. "That's a whole lot of time on two burglaries," said Fairfax Assistant Commonwealth's Attorney Corinne J. Magee, who is prosecuting Killian on the Fairfax escape charge.

"The system has pummeled this man," said Robert S. Letnick, Killian's court-appointed attorney. "In Fairfax County he wouldn't have gotten more than a few months on the same charges."

Asked Danville Commonwealth's Attorney William Fuller, who prosecuted Killian in 1975 on the first burglary charge that brought an eight-year sentence: "What's wrong with those Fairfax prosecutors that they think eight years is a lot? . . . The judge who sentenced him was not a real tough judge."

The escape in Fairfax was not Killian's first, however. He skipped his bond while awaiting trial on his first burglary charge in early 1975 and was hauled back to court by a bail bondsman. He also walked away from a drug rehabilitation program that had been ordered as a condition of his parole in 1977.

When his probation officer ordered Killian to turn himself in, Killian said he responded: "If I'm going back to jail, you'll have to catch me." He was caught several months later walking out of a store in Great Falls, S.C., with a bottle of Cold Duck he hadn't paid for, Killian said. He also served five months in prison in Georgia after a 1973 conviction on charges of possession of marijuana in Georgia.

Court records show Killian was sentenced to eight years in prison by a Danville judge after his conviction on a charge of stealing the stereo from his stepbrother's house. He was sentenced to three years in prison on the charge of stealing $5 from a soft-drink machine in Pittsylvania County.

After serving five years of those sentences, Killian said he took advantage of a sleeping guard to escape from a road gang ditch-digging project near Camp 30 in Fairfax. "I was tired being locked up," Killian said in an interview at the county jail yesterday. "I was wondering myself if I could make it on the streets."

Using another man's lost driver's license to establish his identity as Andrew Adkins, Killian found success: A $19,000-a-year job as a route salesman for Pepsi-Cola, two cars, a motorcycle, a mobile home, a wife and child. But Adkins lived in the shadow of Killian. Other than an occasional steak cookout or trip to the dog races, he and his wife seldom socialized.

"I didn't let myself get close to a lot of people," Killian said yesterday. "I was scared of getting them involved in it. I didn't want anybody charged with harboring me."

Yet, Killian had confided in his wife, a woman nine years his junior that he married shortly after his escape. They married under his assumed name and gave their son his assumed name. "My wife couldn't deal with it," Killian said. "She kept saying that at any time I might be gone--be taken away."

The two split up eventually and his wife told police his true identity, Killian told the court. In the interview yesterday, Killian looked back on his escape, which occurred six days after he was turned down for parole a second time, and said, "It was wrong to leave, but I just needed to be free."

The escape, Killian added, has only added to his problems: "I know that if I didn't have that escape, I'd have been out on parole now for sure."