ORANGE -- Convicted double murderer James H. Long Jr. was found dead in his cell at the Central Virginia Regional Jail on Sunday.

According to jail Superintendent Glen Aylor, jail staff found Long unresponsive in his cell early Sunday morning. Despite CPR procedures performed on Long by jail staff members and rescue personnel, Long could not be revived.

Aylor did not say what caused Long's death, adding that the Virginia State Police are conducting an investigation.

Long was serving consecutive life sentences for killing two Orange County residents in 2005.

State Police Sgt. Mike Woodard said it is customary for the state police to investigate when a prisoner dies while in custody, and an autopsy is standard procedure.

State police spokesman F.L. Tyler said an autopsy was performed on Long's body Monday at the medical examiner's office in Fairfax.

"The cause of death is pending the results of the toxicology exam," Tyler said. There were no apparent signs of injury, he added.

"It does look like he may have had a heart attack," Orange County Commonwealth's Attorney Diana Wheeler said.

She speculated that Long's health had been affected by his lifestyle prior to incarceration. "He'd abused cocaine for years and years," she said.

According to Wheeler, Long was alone in his cell when jail staff found him.

At Long's second trial in February, he was found guilty of the March 2005 shooting deaths of William Browning and Vicki Truax, both of Burr Hill in Orange County. Long was serving two consecutive life sentences for the murder convictions and eight additional years on weapons charges.

Long had already been tried -- and was convicted in 2006 -- of the first degree murders of Browning and Truax, but the case was never permitted to progress to the sentencing phase.

Before that could happen, Judge Daniel Bouton reversed the jury's guilty verdict and ordered a new trial for Long. Bouton overturned the conviction after finding that certain evidence -- a plea agreement between the prosecution and one of its principal witnesses, Robin Browning -- was not provided to the defense.

Long was being held at the regional jail awaiting transport to a state prison. -- Media General News Service