The charges stem from the death of Mr Kumar in his Henderson dairy about 7.30am last Tuesday. He was found stabbed in the neck.
The 12-year-old's father — who cannot be named as it would reveal the identity of his son — is facing four charges of aggravated robbery, committing burglary with a weapon, threatening to kill or cause grievous bodily harm, and unlawful assembly.
Meanwhile, the Herald can also reveal that the mothers of both boys have been taken to the Tenancy Tribunal by their landlords, owing thousands.
The 13-year-old alleged killer's mother — who is also currently before the courts — was one of three tenants of a rental property who in 2011 were ordered to pay their landlord more than $1200.
The 12-year-old's mother, as the sole tenant responsible for a rental property, fled the house owing the landlords more than $4,200.
In 2008, the Tenancy Tribunal made an order for the woman, to pay "immediately" for the extensive damage caused to the property — none of which has been recovered.
"On the evidence presented, I am satisfied that the property was damaged during the tenancy," the tribunal decision reads.
"In particular, all the light bulbs were missing from the premises, the windows were broken in two bedrooms, the back door and the sleepout.
"The oven door was broken and the knobs were missing for the stove top.
"The locks on the back door, front door and the garage door were damaged and needed to be replaced. The sink plugs were missing.
"The tenant [also] breached her obligation to leave the premises reasonably clean and remove all rubbish."
The landlords are still chasing the money owed.
The Herald understands all four parents of the two accused boys have either historical criminal records or are currently before the courts. Approached this week, neither family wanted to talk.
The grandmother of the 13-year-old said she shouldn't talk about her grandson, but added her "condolences" for Mr Kumar's family.
Family history
• 13-year-old: Charged with murder of West Auckland dairy owner Arun Kumar and aggravated robbery.
• His mother: In the past 10 months has faced charges for allegedly stealing a Ford Falcon, entering a house with the intent to commit a crime, and breaching bail. In 2011, along with two other named tenants, she was ordered to pay $1,215.12 in rent arrears by the Tenancy Tribunal.
• 12-year-old: Charged with aggravated robbery.
• His father: Charged with aggravated robbery, committing burglary with a weapon, threatening to kill or cause grievous bodily harm, and unlawful assembly.
• His mother: Still owes landlords $4,211.18 from 2008 when she fled her rental property, having caused damage to the windows, doors, locks, bolts, oven, stove and sinks. The Tenancy Tribunal found against her, but a bailiff was unable to locate her to pay.
