MIRAMICHI, N.B. -- Two young Halifax men with a history of violence have been charged with assaulting Dennis Oland in a New Brunswick prison.

Convicted killer Cody Alexander Muise and Aaron Marriott, who was convicted in a 2008 drug shooting, are alleged to have attacked Oland at Atlantic Institution in Renous, N.B., on July 31, a court official confirmed Thursday.

The 48-year-old Saint John financial planner had been jailed for 10 months after a jury found him guilty of second-degree murder in the 2011 bludgeoning of his multi-millionaire father, Saint John businessman Richard Oland.

He was released on bail on Oct. 25, after the New Brunswick Court of Appeal overturned his conviction and ordered a new trial, citing an error in the trial judge's instructions to the jury.

Muise and Marriott both appeared in Miramichi provincial court on Jan. 12. Neither has entered a plea, and are scheduled to return to court on Feb. 9.

Muise was convicted of first-degree murder for killing Brandon Hatcher in December of 2010 in a gun battle in suburban Halifax, and is serving a life sentence.

According to multiple media reports, Marriott was sentenced to 15 years for a 2008 drug shooting outside the IWK Health Centre in Halifax.

RCMP in Blackville, N.B., which investigated and laid the charges, didn't issue a news release at the time and the prison didn't issue a public notification of the assaults.

"Sometimes we put out releases and sometimes we don't. ... There are some cases of assaults that occur in the province that aren't reported on. It depends on the circumstances in certain situations," said Const. Hans Ouellette.

The police declined to give further details on the case, and the Crown also declined comment, as did defence counsel for Oland.

Crown prosecutors have announced they plan to appeal the Oland decision to the Supreme Court of Canada.

Oland's defence team expects to cross-appeal, possibly seeking an acquittal instead of a retrial.

If a new trial goes ahead, it is not expected to be heard until next year.

The prison in Renous, about 40 kilometres southwest of Miramichi, is a maximum security facility.