The PSNI said it was a “complex and challenging investigation which garnered huge public and media interest, along with widespread speculation” and the eventual outcome was “devastating”.
Assistant Chief Constable Davy Beck said there was “no action that police could have taken” that would have prevented Noah Donohoe’s death.
He added it was important to reflect on any learnings and “ensure they are applied in the future”.
He said: “Noah was a child with his whole life ahead of him. His death is a tragedy, and our thoughts remain firmly with his family and those who loved him.”
Infrastructure Minister Liz Kimmins said Fiona and Noah’s family are at the forefront of her mind.
“As Minister, I will make sure the department does everything it needs to ensure all lessons are learned.”
Noah went missing on Sunday, 21 June 2020, after leaving his south Belfast home on his bicycle, sparking a huge search across the city.
He was found dead six days later in the water tunnel in the north of the city, which leads into Belfast Lough, with the cause of death found to be drowning.
Eyewitnesses, who were the last to see him in the vicinity of the tunnel, reported that he was naked.
The incident sparked widespread speculation about what happened to Noah, with his family launching a high-profile campaign.
There was no conclusive evidence at the inquest about why Noah was without his possessions and all the clothing he was wearing when he was last seen alive.
There was also no evidence about any physical interaction between the schoolboy and anyone else during his journey from his south Belfast to the north.
