The father of a five-year-old boy slain in 1975 has vowed to murder the man who did it "as aggressively and painfully as he killed my son" if he is released from prison early.

John Foreman told WPRO-AM radio that he blamed himself for accepting a plea deal that saw Michael Woodmansee convicted of the second-degree murder of his son Jason in South Kingstown, Rhode Island.

Woodmansee was sentenced to 40 years in prison in 1982, but the plea bargain deal allowed him to be released early for good behavior. This could happen as soon as August, the Providence Journal reported.

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In the interview, Foreman claimed a journal kept by Woodmansee, which has not been released by police, details how the killer had eaten the young boy's flesh.

"I do intend, if this man is released anywhere in my vicinity, or if I can find him after the fact, I do intend to kill this man," Foreman added.

"I cannot think, I cannot sleep. All I think about is trying to find a way to get this man to kill him," he told WPRO-AM.

Foreman said he wanted to kill Woodmansee "as aggressively and painfully as he killed my son."

He said he remembered only one detail contained in the journal, that Woodmansee "ate the flesh of my son."

In the interview, Foreman said his decision to accept a plea deal had been "spineless."

"I've got myself to blame for that ... allowing him to be released early to become a predator to someone else. I'm to blame for all that and I'll make that right," he said.

Foreman said his son was a "well-behaved boy, very smart, very intelligent for his age."

He added that he had been full of "hopes and dreams" for his son. "I know he was going to be somebody. I had real hopes for this young boy," Foreman said.

Amy Kempe, a spokeswoman for Attorney General Peter Kilmartin, said in a statement Monday that he was concerned and outraged about Woodmansee's scheduled release, The Associated Press reported.

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Kempe said Kilmartin had asked Rhode Island's Department of Corrections to look into ways to keep Woodmansee in prison.

Kempe added that the attorney general's office would work with the Department of Corrections to examine the legal options.

Patricia Coyne-Fague, chief legal counsel for the Department of Corrections, said that the only way an inmate could lose his entitlement to early release for good behavior was if he did something wrong.

Coyne-Fague said the early release was based on a law first introduced in 1872. It was last changed significantly in 1960.