A contract killer who set fire to a house to murder a Wollongong solicitor in 2011 will spend at least 24 years behind bars.

Bernard Justin Spicer was the last of four people to be sentenced for the murder of Katie Foreman.

The court was told Spicer was paid $3,000 by Ms Foreman's boyfriend Bradley Max Rawlinson and the woman Rawlinson was having an affair with, Wendy Evans, to light a fire in the lawyer's bedroom with petrol and a lighter while she slept.

In sentencing Spicer, Justice Ian Harrison said the crime was "pathetic, callous and brutal".

"I am satisfied beyond reasonable doubt that Mr Spicer was part of a joint criminal enterprise to kill the deceased," Justice Harrison said.

"It is difficult to be satisfied that he has any remorse for his actions."

Spicer was given a 32-year jail term, but can apply for parole after 24 years.

His three co-accused, including Rawlinson, Evans, and Spicer's then-partner Michelle Proud, were convicted and sentenced in July last year.

Rawlinson was sentenced to 36 years with a non-parole period of 27 years, Evans was given 24 years with a non-parole period of 18 years and Proud will serve 20 years but can apply for parole after 14 years.

A 'frightening and excruciating' death

When fire crews arrived at Ms Foreman's house in 2011, they found her body on the landing outside her upstairs bedroom.

A post-mortem examination revealed her clothing contained traces of petrol.

There was only one way in and out of the bedroom and it is believed that was well-alight when Ms Foreman tried to get out.

Justice Harrison described the fire as "an inferno that exploded in the quiet of night".

"[Ms Foreman] died alone with no possible chance of escape from the blaze," Justice Harrison said.

"It is difficult to contemplate a more frightening and excruciating way to die."

Boyfriend and secret lover wanted victim dead

During the trial, the court was told Rawlinson and Evans were having an affair and wanted Ms Foreman dead so they could be together.

The Crown claimed Rawlinson was the mastermind behind the murder plot, then Evans hired Spicer and Proud to "scare" Ms Foreman.

The last of Katie Foreman's murderers has been sentenced. ( Image courtesy Greg Totman/Illawarra Mercury )

Eventually, it was Evans and Spicer who sneaked into Ms Foreman's home at Corrimal near Wollongong just after 2am on October 27, 2011, using two keys given to them by Rawlinson.

Spicer's lawyers claimed their client was specifically told Ms Foreman would not be home and that the original plan was just to set fire to her car.

The defence said Spicer never intended to kill Ms Foreman, but the jury was not persuaded.

He was found guilty of murder on December 5 last year.

Justice Harrison praised the work of the detectives on the case as "nothing short of remarkable".

Spicer and his co-accused were arrested 55 days after the 31-year-old solicitor died, following extensive phone tapping surveillance and forensic investigation by police.