Methamphetamine cook Noel Alan Percy shot Brendon Roy Marriott dead in December 2010.

Mr Percy told police he acted in self defence, because he said that Mr Marriott, 41, who distributed Mr Percy's product, had threatened him and his family.

Police charged Mr Percy with Mr Marriott's murder, but the accused committed suicide, aged 40, in Risdon Prison while awaiting trial in May 2012.

Coroner Rod Chandler, in a decision dated January 22 this year, found that Mr Marriott died after Mr Percy shot him multiple times.

The Parole Board's decisions in the parole applications of Shelly Anne Percy and Anna-Lyce Maree Olding were published this week.

Mrs Percy was Mr Percy's wife, while Olding was Mr Percy's mistress.

In the Hobart Supreme Court on June 6, 2013, Mrs Percy was convicted of having perverted the course of justice, failure to report the killing of a person, and having sold and supplied a controlled drug.

She was sentenced to 15 months' jail, with a non-parole period of 7 1/2 months.

Mrs Percy, 41, was paroled from January 20, 2014, to September 5, 2014.

The Parole Board noted that she failed to report her husband's killing of Mr Marriott, after she was told that her husband had shot Mr Marriott and after her husband disclosed to her where Mr Marriott's body was located.

Olding, 27, was paroled from February 26, 2014, to May 25, 2015.

She had been convicted in the Supreme Court on December 21, 2012, of having manufactured a controlled drug for sale, having perverted the course of justice and failure to report the killing of a person.

Olding was jailed for 30 months, with a non-parole period of 15 months.

The Parole Board noted that her perverting justice and failure to report the killing of a person offences related to her conduct, when attempting with Mr Percy, to frustrate investigations into both a drug lab operation and Mr Percy's killing of Mr Marriott.