WA boxer Danny Green has taken to social media to congratulate the person who put murderer Trudi Lenon in hospital.
Lenon, who sustained burns to 30 per cent of her body after having boiling water thrown on her, is awaiting sentencing in Bandyup Women's Prison for the murder of Aaron Pajich.
Lenon and co-offender Jemma Lilley killed 18-year-old Mr Pajich at their Orelia home in 2016.
She remains in hospital following the attack which happened at the prison earlier this week.
In referring to burns sustained by Lenon on her "putrid body", Green said his "hat is off to whoever carried out this act".
"Her and the other mutt murdered an innocent 18-year-old stranger who was autistic in absolutely disgusting and horrific circumstances," he said on social media.
"This poor young man.
"The way his life ended was just incomprehensible."
Green expressed his wish for Lenon to "get an infection and die a horrid and slow and obscenely painful death".
He then referred to the killer as a "foul mutt".
Green, who has been outspoken in the past over one-punch attacks he calls "coward punches", attracted plenty of support from his more than half a million followers.
"I'm willing to write what many think," he said.
An investigation is under way into the attack on Lenon, with no charges yet laid.