Constable C suggested to Constables A and B to use a restraint belt, but Constable A decided that was unnecessary.
Bell had not exhibited any at-risk behavior and there weren't alerts in the police database of previous self-harm behaviour.
Arriving at his house about 3.10am, Officer A took Bell to the house to find the front door locked.
Bell climbed in through an open window and let Constable A inside.
He found his medication from the kitchen before grabbing a pair of trackpants before turning to the officer and saying "tell my kids I love them" and suddenly self harming.
The officer immediately activated his officer safety alarm and called for help and then trying to help Bell.
Officer B arrived inside the house together with Constable A and began carrying out first aid.
St John Ambulance staff also arrived and despite their best efforts, Bell died at the scene.
Bell's blood alcohol returned a level of 52 mlg, just over the legal drive limit of 50mlg. He was also found to have 0.06mlg of methamphetamine in his blood.
The Police National Operations Investigation Group report found Constable A's actions did not amount to a major departure from the standard of care expected. He was also found not to have acted negligently or in a physical manner that caused harm to Bell.
However, Bell's father, Puni Bell, wrote to the Coroner with a number of concerns around his death and police processes.
Bell's partner also wrote to Coroner Louella Dunn stating that had she been asked, she would have collected his medication.
Dunn said family expressed concerns that Bell should have been restrained when taken back home.
"I understand the concerns of William's whanau and sympathise with them. However, the police officers had no reason to believe that William was at risk of self-harm.
"Some of the questions raised by family could not be answered on the evidence before me or were outside the scope of my inquiry."
Coroner Dunn ruled that Bell's death was self-inflicted.
She did not make any recommendations.
WHERE TO GET HELP
• Lifeline: 0800 543 354 (available 24/7)
• Suicide Crisis Helpline: 0508 828 865 (0508 TAUTOKO) (available 24/7)
• Youth services: (06) 3555 906
• Youthline: 0800 376 633
• Kidsline: 0800 543 754 (available 24/7)
• Whatsup: 0800 942 8787 (1pm to 11pm)
• Depression helpline: 0800 111 757 (available 24/7)
• Rainbow Youth: (09) 376 4155
• Helpline: 1737
If it is an emergency and you feel like you or someone else is at risk, call 111