Det Supt Terry Mann on the steps outside the Sheffield club where Joshua Green was stabbed to death in the early hours of New Year's Day.He made a fresh appeal for information despite already speaking to many of the people in the club that night.
"While many people have provided us with statements others have chosen to stay silent or have refused to help."
Four people are answering bail in relation to the killing but no-one has been charged.
More top news
Figures show that 225,000 people develop dementia every year in the UK - and it isn't a conditition that only affects the elderly.
A preliminary investigation into Rotherham's child sexual exploitation scandal is starting.
The latest weather forecast for the Calendar region