A woman who helped try to cover up a Perth murder has been fined for breaching a condition of her suspended jail term.

Kay Ann Kosick was given a two-year suspended term, after pleading guilty to being an accessory after the murder of 30-year-old David Blenkinsopp.

He disappeared in March 2012 and his body was found three weeks later at Pinjar on Perth’s northern fringe.

He had been ambushed by his killers in Wanneroo, and was run over and shot.

Kosick admitted helping clean blood from a car, allowing Mr Blenkinsopp’s killers to use her shower, and repeatedly lying to police.

In the Supreme Court this week, she pleaded guilty to failing to attend a counselling program in January which was a condition of her sentence.

The court heard she also tested positive for cannabis.

Kosick maintained the breaches were a result of the stress of giving evidence at the February trial of Mr Blenkinsopp’s killers, one of whom was her former husband.

Justice Lindy Jenkins fined Kosick $150, and told her that while the court had taken a lenient approach for this offence, it would not if there were further breaches.

In April Kosick’s former husband Damien, along with Tamara Broadbent and Gary Young, were found guilty of Mr Blenkinsopp’s murder.

Damien Kosick was sentenced to life with a 22-year minimum, while Young and Broadbent, who was Mr Blenkinsopp’s former lover, were both given life with a 24-year minimum.

A fourth man, Kym Foster was found guilty of manslaughter and sentenced to eight years’ jail.