Betty M. Holler, 38, who has testified she arranged the murder-for-hire killing of a Fairfax County service station owner, pleaded guilty yesterday in Fairfax Circuit Court to a reduced charge.

Fairfax Commonwealth's Attorney Robert F. Horan Jr. agreed to amend the charge of capital murder, for which Holler could have faced the death penalty if convicted, to first-degree murder as an accessory before the fact.

Horan said Holler had cooperated in the prosecution of other defendants in the case.

Speaking softly, Holler entered her plea before Fairfax Circuit Court Judge Thomas J. Middleton, who set sentencing for Jan. 26. Holler faces a possible sentence of 20 years to life imprisonment.

Horan said yesterday he will recommend 25 years' imprisonment for Holler, but Middleton is not bound by the recommendation.

Holler has testified in court that she helped to arrange the Jan. 31 slaying of George Harold Scarborough at the request of his estranged wife, Jamie A. Scarborough.

Holler said she hired two Clinton, Md., men, Charles D. Stewart and James T. Clark Jr., to kill Scarborough and passed $7,000 from Mrs. Scarborough to the killers.

Scarborough, 45, was shot to death as he entered his town house at 6541 Yadkin Ct., Franconia.

Stewart and Clark have been convicted of murdering Scarborough. Clark has been sentenced to death; Stewart is scheduled to be sentenced Tuesday. Jamie Scarborough was acquitted Oct. 27 by a Fairfax County jury of complicity in her husband's death.

Holler was the prosecution's key witness at Scarborough's trial. Afte the verdict was returned, Horan remarked that the jurors "believed the defendant over Betty Holler" and that Holler and Stewart "evidently were not believable to the jury."

Following Holler's trial yesterday, Horan said he still believes that a fourth person was involved in the murder-for-hire plot. "She (Holler) didn't have $7,000," he said.

At yesterday's trial, Horan introduced into evidence a 33-page statement by Holler, in which she outlined the alleged plot to the police.

In that statement, Holler said Scarborough wanted her estranged husband killed because "she wanted to get even with" him.

Holler said that when she received a telephone call that '"the beast is deceased," she knew the plot had been carried out. "I almost went into shock. I went in the bathroom and I started crying and then I looked in the mirror and I was white as a ghost..."

After Scarborough had been killed, Holler said she received threatening calls from Stewart and Clark. She said the men "warned me that I better not even think of turning state's witness."

She also said Jamie Scarborough warned her not to talk to police unless she had an attorney present.