OTTAWA - Serial killer Clifford Olson has launched a grammatically-challenged legal threat at the Harper government over its plan to end pension payments to federal inmates.

"It should be brought to your attention, That I still pay TAXS and file the FEDERAL TAXS," Olson wrote in a June 16 letter to a federal cabinet minister from his Quebec prison cell.

"I look forward to a court case I will be bring if the Bill you want to remove my Old age Pension I have paid into."

Olson fired off his three-paragraph missive two weeks after Ottawa announced legislation that would end pension payments to federal inmates.

The government was responding to outrage over the revelation that Olson was eligible to collect $1,100-a-month in old age security and income supplement benefits.

Olson has spent the last 28 years in prison for killing at least 11 boys and girls in British Columbia.

The new bill would deprive about 400 federal prisoners of about $2 million a year in benefits if it becomes law.

Ottawa is also hoping to persuade the provinces and territories to cut off benefits to 600 prisoners in its jails, which would save another $8 million.

Human Resources Minister Diane Finley introduced the legislation last month.

Finley's spokesman Ryan Sparrow said Thursday the government remains steadfast in its intent to deprive inmates of the seniors' benefits.

"Obviously Canadians are outraged that prisoners like child killer Clifford Olson are receiving taxpayers' benefits," Sparrow said.

"Clifford Olson already has his basic needs met in prison, and our Conservative government believes it is wrong that prisoners who break the law should receive taxpayer-funded old age security."

Sparrow said Olson's objections are "deeply insulting" to his victims.

In his letter, Olson says he wants to "obtain" a copy of the bill that has been introduced in Parliament.

Olson is eligible to apply for parole but it is unlikely he will ever be released from the Quebec maximum security prison in Ste. Anne-Des-Plaines where he currently resides.