The 21-year-old father killed on Sunday night in Ħamrun suffered five stab wounds that penetrated his vital organs, including his heart, medical sources told the Times of Malta.

As investigations continued throughout the day yesterday, the theory being followed is that the motive behind the murder was the well-being of a five-year-old boy.

The matter seems to have been the cause of a fight between the boy’s father and his mother’s partner.

Sources said the brawl was sparked by claims that the boy was mistreated by the victim, Brandon Pace, who died when he was stabbed at the entrance of his apartment in Giovanni Barbara Street.

The alleged aggressor, Kurt Grech, who had a child with a woman who recently started dating the victim, told investigators Mr Pace had been mistreating his infant son. The argument had started several weeks ago over social media and escalated over the last couple of days.

The two argued over the phone on Sunday. But apparently, the matter was far from settled, and Mr Grech went to Mr Pace’s home, accompanied by his parents and brother.

Mr Grech suffered a chest wound in the brawl, which also involved several floor tiles being hurled.

Mr Grech’s mother was also injured. The family fled the scene but was arrested shortly after and hospitalised.

The sources said the police could not proceed with the arraignment yesterday because doctors had not given their green light for Mr Grech’s release from hospital. An arraignment is expected today.

Criminal action is also expected to be taken against the Grech parents, even though Mr Grech is likely to be accused with dealing Mr Pace the fatal blows, the sources added.

They said Mr Pace had been in jail and only released recently after completing a drug rehabilitation programme. He died in the arms of his sister, Donna, who took to Facebook yesterday to express shock at her brother’s death.

Even his partner, who witnessed the attack, said she could not believe that Mr Pace, who had had very little opportunity to spend with her children – because he was in jail – had been killed.

His was the fifth murder so far this year.