Seven months after being released from prison, a Camden man is accused of killing the witness who helped put him away.

Richard Santiago, 55, was released May 6 after serving six years in prison for the 2004 stabbing death of 44-year-old Richard King of Mantua, who was visiting his girlfriend at the Woodbury apartment complex where Santiago lived.

One of the witnesses who testified against him was King's girlfriend, Ramona Johnstone, who had been watching a football game on television when a fight broke out outside her apartment between King and Santiago. King stumbled back into the apartment, bleeding from stab wounds, and later died.

Santiago was charged with murder, but in a 2006 trial the jury found him guilty of aggravated manslaughter.

On Monday night, the 54-year-old Johnstone was found unconscious in the same apartment she was living in at the time of King's death with multiple stab wounds, according to the Gloucester County Prosecutor's Office. She was dead by the time she arrived at Underwood-Memorial Hospital.

Superior Court Judge Walter L. Marshall Jr. set Santiago's bail at $1 million on murder, weapons, and hindering-prosecution charges.

"Oh, my God, I need to sit down," said Amelia Santiago, the suspect's sister, when reached by telephone Friday. "I sincerely believe he did not do it. That woman's death is coincidental. They have to look into this."

At the time of the trial in 2006, Johnstone worried about what might happen when Santiago was released, her sister Rainy DePaulis said Friday.

"When it first happened, she was worried. That he wouldn't be in there that long, because they only found him guilty of manslaughter," DePaulis said. "I don't think anyone notified her when he was released."

A spokesman for the Gloucester County Prosecutor's Office said that only victims, not witnesses, are notified of inmate releases, and that he did not believe any steps had been taken to protect Johnstone.

"Usually if there's a perceived threat, there can be some protection. But I don't know of any expressed threat," said Bernie Weisenfeld, the spokesman.

Since being released from South Woods State Prison in Bridgeton, Santiago had been staying with his sister in Camden, rarely leaving the house except to visit his psychiatrist or his parole officer, his sister said. He has an 18-year-old daughter who was recently diagnosed with cancer, she added.

"He hardly left the house," Amelia Santiago said. "He was trying to get back on his feet."

After Johnstone was found dead Monday, Santiago quickly became a suspect and investigators contacted his parole officer to determine his whereabouts, Weisenfeld said.

On Wednesday, Santiago was arrested for violating his parole and was sent to the Camden County Jail.

He was found with pills and had been drinking, his sister said.

Santiago had been sentenced to a nine-year prison sentence but ended up serving six years. The sentence required him to serve at least seven years, and he was given credit for the time he spent in jail before the trial in 2006, Weisenfeld said.

New Jersey State Parole Board officials did not return a phone call for comment.

Contact James Osborne at 856-779-3876 or jaosborne@phillynews.com or follow on Twitter @osborneja.