The killer of Canberra woman Tara Costigan has appeared alongside four other prisoners charged with bashing two brothers in prison.

Marcus Rappel, 43, along with 28-year-old Daniel Grech, 30-year-old Alex Bourne and 26-year-old Jeremy Reid were all remanded in custody at the ACT Magistrates Court.

A fifth alleged offender, 31-year-old Isileli Taholo, has been returned to immigration detention at Villawood in Sydney.

The group is accused of an attack on two brothers whom police said were hospitalised after the incident.

Rappel is serving a 32-year sentence for the 2015 murder of Ms Costigan.

He attacked his ex-partner with an axe after forcing his way into her house, and killed her while she was holding their week-old baby.

The case will return to court in January.