Dramatic courtroom moment woman accused of stabbing her boyfriend to death learns he was sleeping with her friend as their junkie home from hell is revealed

A woman accused of murdering her boyfriend in a suburban drug den has stormed out of court after learning she had not been his only lover.

Linda Lee Falzon, 43, is accused of murdering James McColgan, 61, at his home in Sunbury, on Melbourne's north-west edge, where the pair lived with other addicts and drug dealers.

On Tuesday, Falzon learned that her friend had also slept with Mr. McColgan, causing her to walk out of the jail's media room where she had been watching a preliminary hearing that will determine whether she faces trial.

The Melbourne Magistrates' Court heard Falzon is accused of stabbing a knife into Mr McColgan's chest and leaving him to bleed on the ground.

No motive has been established for the tattoo artist's alleged murder, while several other people have been identified as possible suspects.

One of those people allegedly told Falzon to stab McColgan with a screwdriver.

The house had been given to Mr. McColgan by his mother and converted into a suburban cesspool where junkies gathered to sell, buy and use drugs.

Linda Lee Falzon has been charged with the murder of her lover James McColgan

At the time of his death, Mr. McColgan had just received $100,000 in damages for being the victim of sexual abuse as a child.

Samantha Attard – who was 23 years younger than Mr McColgan – had kept her sexual relationship with Mr McColgan secret until Monday, when she told Falzon's lawyer Adam Chernok.

It was Mrs Attard who found Mr McColgan's bloody body and reported it to the police.

The court heard that Mr McColgan owed Ms Attard thousands of dollars at the time and had promised to buy her a car.

'Because of the age difference, I didn't want to say anything to anyone. I am the same age as his son,” Mrs Attard told the court.

The court heard that Ms Attard had slept with Mr McColgan behind Falzon's back for five months before his death.

But it was her description of how the pair first established their relationship that sent Falzon storming out of the Dame Phyllis Frost Center media room.

Linda Lee Falzon stormed out of court when she learned her late lover had cheated on her

'He came over and stood behind me and said, 'I think I'm going to kiss you.' We were very close, had a lot in common, always made each other laugh and it just went from one thing to the next,” Ms Attard told the court.

“Because of my age, I didn't want to say too much to anyone.”

Falzon refused to return to the hearing, forcing Mr Chernok to continue without her.

Ms Attard said Falzon had no idea she had slept with her boyfriend.

Falzon had been in contact with Mr McColgan while he was homeless.

The court heard police found Mr McColgan bleeding at the front door of the house and he died at the scene, despite paramedics' attempts to revive him.

Police who visited the house described it as filthy, with dirty, uncapped syringes everywhere.

Mr Chernok said the house was littered with food scraps and the rooms were full of 'trash and debris'.

The filthy drug den where Linda Lee Falzon allegedly stabbed her two-time lover to death

Linda Lee Falzon was found hiding in this backyard after the house was apparently cleared by detectives

Such was the nastiness: An unarmed officer found Falzon in the backyard, hiding behind a discarded shopping cart, after detectives had supposedly “secured the crime scene.”

Ms Attard told the court that about six people and a dog had stayed at the house, with at least eight people a day attending to buy drugs from a dealer who lived there.

She told the court that the people staying in the house were taking drugs and smoking both cannabis and methamphetamine.

She told the court that one of the residents once threatened to “cut her into pieces from top to bottom.”

It was known that the man went 'crazy' with a hammer and destroyed the place.

Ms Attard said on one occasion the man told Falzon how to commit murder in what was described as 'the screwdriver incident'.

'You know what to do. Drive it. Drive it hard,” Mrs Attard recalled him saying.

“I overheard a conversation between him and Mrs. Falzon.”

The hearing continues.