One of the Illawarra's most notorious killers has fronted court over a jail-yard gang-bashing that almost killed one of the infamous "K" brother pack rapists.Triple murderer Matthew Wayne de Gruchy is one of four convicted killers charged over the attack, which also allegedly involved two sex offenders and a man serving time for armed robbery. De Gruchy is serving a 28-year sentence (21 years minimum) at Goulburn jail for murdering his mother and two siblings at the family's Albion Park Rail home in 1996. Yesterday he appeared via videolink at Goulburn Local Court.His legal representative entered not guilty pleas to four assault charges, including two charges of maliciously inflicting grievous bodily harm.The charges relate to an assault on the two eldest of the four "K" brothers - so-called because their identities cannot be revealed for legal reasons - in the exercise yard of the jail in February 2007.The brothers were convicted in 2002 of gang rapes in Sydney, including that of NSW Woman of the Year nominee Tegan Wagner.The attack resulted in the second-eldest of the brothers, known only as MAK, requiring brain surgery. His older brother MSK was treated for a broken arm. Yesterday's matter was adjourned to May 13 so police could serve a brief of evidence.Also before the court was another man, who can not be identified and is serving a minimum 34-year sentence for the 2001 suffocation murders of three children in Cabramatta, and Jay William Short, imprisoned for 20 years for the murder of 19-year-old Lithgow beauty queen Alison Marie Lewis in 1997.Killer Shannon Leigh Daley, Adrian Gray (armed robbery), Ghebli Djait (drink spiking-related sexual assault) and Robert John Hayes (sexual assault) were also charged over the matter.De Gruchy, now 31, has never explained why he took the lives of a woman and two children on the night of March 12, 1996. All were bashed on the head with a weapon similar to a car jack.The slayings were so gruesome the first police officer on the scene never returned to work again. De Gruchy is eligible for parole on June 21, 2017.