When Gary Worth took some friends to inspect his rental property in Fairfax County last weekend, he found himself looking down the barrel of his tenant's shotgun.

"He's rather fortunate I . . . didn't exercise my option to use that gun," said Donald Bernardo later.

Instead he had his landlord arrested on charges of trespassing and vandalizing the property.

"I'm being accused of trespassing on my own property and vandalizing it," fumes Worth.

So began another episode in the drama of Worth versus Bernardo, an extraoridinary tenant-landlord civil dispute that has grown progressively less civil.

"Mr. Bernardo . . . has certain problems," says Worth's lawyer.

"They're trying to take the law into their own hands," replies Bernardo.

At issue are a $150,000 three-bed-room house, swimming pool and barn and the 2 1/2 acres on which they sit in the Virginia suburbs.

Worth, a communications executive who owns the property, wants it back. But Bernardo, an airplane broker, who lives on it with his wife, two sons, a horse and a dog says he isn't about to leave -- voluntarily.

"Until the courts say that [Worth's] entitiled to possession of the property," says Bernado's lawyer, "my man's going to stay there. It's that damn simple."

It is, says Worth's lawyer, a classic example of the age-old axiom that posession is nine-tenths of the law.

The dispute began last September, when Bernardo was supposed to close an argreement to buy the property, located in the Fairfax Station area, for $151,000. Bernardo had been renting the house from Worth since the previous August, and had given him $15,000 in down payments.

When Bernardo, despite extensions on the deal, couldn't come up with the needed cash, Worth filed suit. "My hope was that by filing suit I would motivate him to close," he said recently.

Instead Bernardo agreed to give Worth an additional $11,000 in return for another extension.

But Bernardo stopped payment on the check -- the circumstances are disputed -- and the pair turned to the courts.

Since then, their attorneys have papered the Fairfax County Courthouse with legal actions -- and resolved virtually nothing.

Yesterday a Fairfax County circuit court judge admonished both sides to keep their distance and avoid any further confrontations pending an outcome of their court fight.

Worth has filed three seperate lawsuits, asking for repossession of his property and back rent, which Worth claims now exceeds $14,000. Worth won an judgment for the home back in October, but an appeals court overturned his victory

His tenant has taken almost every legal round since then. The second suit was dismissed by a judge who ruled Worth's attorney had failed to submit adequate evidence. The third suit was tossed aside by a judge who ruled he didn't have jurisdiction in the case. The judge later reconsidered and invited Worth's attorney to file the suit again. He did, and it will be heard Sept. 16.

Those "technicalities" that have kept him from his house illustrate the failure of the state's legal system, Worth says.

But Bernardo's attorney, Lionel Richmond, says they show only that Worth's efforts amount to "a comedy of errors."

"The court system doesn't fail if you see it right." Says Richmond. "You get the best lawyer you can to find out how it's used."

"If you're going to bat," he adds with a grin. "I'm a nice guy to have in your corner."

Worth says Richmond told him "he would tie this house up forever, that I'd never be able to sell it." "He's been successful so far," the landlord acknowleges.

With the legal battle continuing, Bernardo and Worth have begun their own guerilla war outside the courtroom.

It was declared early this month, when a tree fell on the house, knocking a hole in the roof. Bernardo demanded that Worth repair the damage, and the landlord went out to inspect last Saturday.

Once there, he disconnected the home's water pump, rmoved the electrical fuses, and padlocked the fuse box. Worth says there was a water leak around the wiring that could have electrocuted someone or caused a fire. Bernardo labels that action simple "harrassment."

The next day, Worth returned to the property with two friends and a pair of armed security guards. Finding that Bernardo had broken the padlock, replaced the fuses and turned the water back on, Worth took out a pair of cutters and sliced through the electrical writing to the house, cutting off the power.

"My wife was hysterical." says Bernardo. "Gary Worth had run around the back of the house with his armed guard."

The tenant moved quickly. He grabbed his shotgun, slammed a shell into the barrel, pointed it at his visitors, and "waltzed them off the property," as he put it.

"I felt physically threatened," Bernardo explained. "I took appropriate action to protect my family and my property."

Worth, who says he will not repair the house until Bernardo leaves, posted guards at the entrance to the property to warn that the house was in dangerous condition and didn't belong to Bernardo.

Bernardo responded by obtaining warrants for the arrest of Worth and one of his friends.

Worth surrendered himself to police on Tuesday, but he says his friend was hauled off in handcuffs.

That day, Worth sent out to the propety a truck loaded with gravel. Bernardo says the rock was to have been dumped in a pile on the driveway, blocking his access to the house. Worth says it was to be spread across the driveway, to improve access to the house for later repairs.

Either way, the truck's driver was dissuaded from his mission when Bernardo asked him to leave -- while his son watched over the scene with a rifle.

Bernardo frankly considers his home under seige. A visitor found the gate to the driveway closed, the property patroled by Bernardo's son, a friend, and a private security guard. Bernardo's wife and a 10-year-old son have been sent to Buffalo to stay with her parents, says the tenant.

"I don't know where it's going to stop," says Bernardo.

Worth, meanwhile, labels Bernardo's charges of harrassment "ludicrous," "I'm harrassing him huh?" he asks, incredulously. "Why doesn't he just leave my house?"

"Once you start something like this," says attorney Richmond. "It's difficult to maintain any kind of reasonable communication between the two sides."