Massimo ''Max'' Sica has been found guilty of the murders of his ex-girlfriend Neelma Singh and her two younger siblings, Kunal and Sidhi, in their Brisbane home in 2003.

It took a jury of eight men and four women nearly four days to reach a unanimous verdict after the longest criminal trial in Queensland Supreme Court history.

The siblings were killed late on Easter Sunday, April 20, 2003, or in the early hours of Easter Monday. It is believed Sica strangled his ex-girlfriend Neelma Singh, 24, and then killed her brother, Kunal, 18, and sister Sidhi, 12, with a garden fork to prevent them telling police.

The siblings' mother, Shirley Singh, rocked violently in her chair as the verdict was read out.

Sica, 41, will be sentenced tomorrow, but he faces up to 45 years in prison.

When asked if he had anything to say to the court after the verdict was read out, Sica said: ''I didn't kill no one and the Queensland justice system is corrupt.''

He showed no emotion as the verdict was read out.

However, outside court his mother was not so restrained

Sica's father, Carlo Sica, put his hand over his wife Anna's mouth and tried to drag her away from the media as she screamed: ''What are the human rights in this country? Nine years I have gone through this.''

As Mr Sica pleaded with her ''Please, please'', his wife yelled: ''You don't see me cry, I am like my son.''

Mr Sica reassured his wife.

''Don't worry, we will appeal,'' he said.

A member of Sica's legal team said it was a difficult time for both families. They have a month to lodge the appeal and will be reviewing the court transcripts.

During the trial, evidence had been given to the court that Neelma died first ''of asphyxiation caused by sustained manual compression of her neck … that is, she was strangled''.

The prosecution case was that 12-year-old Sidhi died next ''from blunt force trauma to her head, inflicted with a severe degree of force''. Kunal, 18, was believed to have drowned in the spa bath where all three bodies were discovered, after suffering ''blunt force trauma to his head''.

The Singhs' bodies were found inside a spa in the main bedroom ensuite on April 22, 2003, by Sica, who said he entered the home about 2.20pm after becoming concerned when Neelma failed to take his calls.

No charges were laid until December 30, 2008, when a forensic investigation was finished, capping an intense police probe of the case.