The grieving loved ones of Melbourne mother Simone Quinlan wore red – her favourite colour – the day her murderers were finally brought to justice.

The 33-year-old was bashed, shot, dumped in a mineshaft and set on fire in August 2015, as punishment for "snitching" on her boyfriend who had hit her in the head with a baseball bat.

During a prolonged attack at his home in Melton, Brendan Neil tormented the woman by beating her and taping up her head, telling her she looked beautiful like that.

His mate Wayne Marmo sat in the kitchen, filing a .22 rifle during the assault.