Warning: This story contains details some readers may find disturbing. Reader discretion is advised.

The child molester was watching PBS Kids again and Jonathan Watson says he simply couldn’t take it anymore.

Inmate Watson, 41, has publicly confessed to beating two convicted child molesters to death at a California prison last month, after one of them allegedly “taunted” him by watching children’s programming in a shared prisoner space. He told his side of the Jan. 16 rampage in a confession letter sent to the Mercury News earlier this week.

David Bobb, 48, died en route to the hospital while Graham De Luis-Conti, 62, passed away three days later. Both victims were serving life sentences for aggravated sexual assault of a child under 14 years old.

“Being a lifer, I’m in a unique position where I sometimes have access to these people and I have so little to lose,” Watson told the Mercury News. “And trust me, we get it, these people are every parents’ worst nightmare.”

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Watson has not yet been charged, but prison officials identified him last month as the person responsible for beating two other inmates to death with a walking cane at the California Substance Abuse Treatment Facility and State Prison in Corcoran, Calif. Watson had only been at the facility for a week after he was transferred there from a higher-security institution. He is serving a life sentence for murder.

Watson says he never should have been transferred to the lower-security facility, where he was placed in a shared prison pod with several other inmates, including one of the convicted child molesters. According to his letter, the first victim seemed to “taunt” their entire pod by watching PBS Kids in full view of the other inmates.

“I could not sleep having not done what every instinct told me I should’ve done right then and there, so I packed all of my things because I knew one way or another the situation would be resolved the following day,” Watson wrote to the paper.

He claims he went to the prison counsellor the next day and asked for an “urgent” transfer to a more secure facility because he was afraid he might turn violent. He says the staffer declined his request, so he went back to his pod.

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That’s when he says he saw PBS Kids on the television again.

“This time, someone else said something to the effect of, ‘Is this guy really going to watch this right in front of us?’” Watson wrote to the paper.

“And I recall saying, ‘I got this.’ And I picked up the cane and went to work on him.”

The prison guards did not notice the first attack, according to Watson’s account. He says he left the pod to tell a guard about what he’d done, but he stopped in his tracks when he spotted a “child trafficker” in a neighbouring cell.

“I figured I’d just do everybody a favour,” Watson wrote to the paper. “In for a penny, in for a pound.”

Afterward, Watson says he went to a guard and reported the killings immediately. He says the guard didn’t believe him until he looked in the dorm and “saw the mess I’d left.”

He told the paper that he gave prison staff a full confession, and he plans to plead guilty to whatever charges he faces.

A homicide investigation is currently underway.

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“We can’t comment on an active investigation,” Dana Simas, a spokesperson for the California Department of Corrections and Rehabilitation, wrote in an email to the Associated Press.

Watson has already served 10 years of his current life sentence, which he received for first-degree murder and discharging a firearm causing great bodily injury or death.

He has been segregated from other prisoners since the attack and is not allowed to use the phone or see visitors, according to the Mercury News. He sent the paper his confession letter in response to an interview request.

Watson said he and many other inmates have sympathy for the victims of child molesters. That’s why he believes those offenders face so much violence from other inmates in prison.

“These families spend years carefully and articulately planning how to give their children every opportunity that they never had,” he wrote. “And one monster comes along and changes that child’s trajectory forever.”

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—With files from The Associated Press