Both men, one a race horse trainer, the other a horse dealer, were well-known and well-liked in the moneyed farms and homes around Middleburg, Va., the main town of Loudoun County's lush horse country.

Now, one of them, Theodore Gregory, 28, the trainer, is charged with murdering the other, Howard LaBove, 30, the horse dealer and sometime trainer, in an incident that has stunned the town.

County authorities said LaBove was fatally shot with a 45-caliber handgun Wednesday night in his cottage on Wolver Hill, the rambling farm of show-horse owner Oliver Iselin, in what authorities described as a domestic argument.

Although authorities would provide no additional details, various accounts said Monique (Mo) Gregory, a riding instructor who is the estranged wife of Theodore Gregory, was with LaBove at the time of the shooting. She fled from LaBove's cottage, according to the accounts, and went to another nearby cottage.

In the picturesque, tree-shaded center of Middleburg, amid the tackshops with their $1,400 saddles, and realty offices advertising million-dollar horse farms, town residents talked quietly, in tones of shock about the incident and their freinds, whom they referred to as Ted, Mo, and H (for Howard LaBove).

"I'm absolutely stunned," said LaOves' partner, Joe Fiore, owner of Rhiannone Farm near Middleburg. "It's incredible, it's ghastly. Howard came here a year and a half ago to be my partner. He was the living best."

Flore said LaBove and Mo Gregory dined with him and some others Wednesday night at Cafe Le Rat in downtown Middleburg. LaBove and Mo Gregory left about 10 p.m. when the dinner party ended, Flore said.

One friend recalled that Mo Gregory had said she expected to be returning about 10 p.m. to her cottage on the Holly Hill horse farm where she lived and taught riding.

Gregory and her husband had separated last June, according to freinds.

Theodore Gregory was arrested yesterday morning at Barn 6 of the Middleburg Training Track. He was being held last night in the county jail in Leesburg after bond of $150,000 was set in Loudoun General District Court.

On the rambling Iselin estate, LaBove's green Chevrolet pickup truck remained parked outside his black and white cottage near the horse barn. Farm employes' children played amid the trees, apparently unaware of what had happened.

"There's nothing sensational about this," said Fiore, LaBove's partner. "This is a tragedy."

A Middleburg shop owner echoed the words. "I'm going to start crying again," he told a reporter yesterday. "I liked them all. It's not a scandal. It's unfortunately something that happened. I'm completely devastated."