Surprising prosecutors and his own defense attorney, a teenager accused of fatally beating a Dale City man and then setting the man's body on fire announced in court yesterday that he plans to plead not guilty to a charge of capital murder.

Benjamin Hugh Hammonds Jr., 18, of Stafford, had been expected to enter a guilty plea at a hearing in Prince William County Circuit Court, part of an agreement with prosecutors to replace the capital murder charge with a lesser first-degree murder charge.

"This morning, he changed his mind," Commonwealth's Attorney Paul B. Ebert said. "He apparently talked to his mother and grandmother, which may have precipitated his change of mind."

Hammonds, who was 17 years old at the time of the killing, faces charges of capital murder, abduction and robbery for his alleged role in the July 1 beating and burning death of Joseph Scott Williams, 32. Police say that Hammonds and Danita Yvonne Corbin, 29, beat Williams in Corbin's Dale City town house, robbed him of $5, and then set his body on fire in an attempt to hide evidence.

Had Hammonds entered a guilty plea yesterday to the first-degree murder charge, he would have faced from 20 years to life in prison with the possibility of parole. Prosecutors said they will once again pursue the capital murder charge. If Hammonds is convicted, jurors will have the option of sentencing him to death or to life in prison without parole.

Police allege that Corbin and Hammonds attacked Williams after an argument, hitting him over the head and leaving him locked in a basement to die. Williams, who was mentally disabled, was a frequent visitor to Corbin's town house.

According to police, Hammonds admitted to detectives that he dragged Williams to woods behind the town house, and with Corbin's help, doused him in gasoline and set him on fire. An autopsy revealed that Williams died as a result of blunt blows to his body, with burning as a contributing factor.

Circuit Court Judge Leroy F. Millette Jr. is expected to set a new trial date for Hammonds this morning to allow his defense attorney, William Baker, time to prepare. Baker said that he had expected a guilty plea and was "surprised" by his client's decision.

Ebert said he had anticipated that Hammonds would testify at Corbin's trial, which is scheduled to begin in two weeks. Hammonds has implicated Corbin in statements to police but cannot be compelled to testify if such testimony would implicate him.

Two 14-year-old boys--Corbin's son and another youth--were present during the attack and likely will be "material witnesses" in both trials, prosecutors said.