Going from that to "Non-white crime is under-reported" is a huge leap and contradicts some other well known facts
For instance you might be aware that research has shown that non-white individuals are disproportionately subjected to stop-and-search police stops, which you would think should mechanically lead to higher recorded crime rates among these groups
"What explains these failings? There are a range of explanations, from lack of understanding and incompetence to snobbery, misogyny and fear of inflaming racial tensions....
"There is evidence that many officials feared being accused of racism. In 2004, a Channel 4 documentary about Asian men grooming girls in Bradford was postponed over fears that it could lead to race riots; Jay found that councillors had fretted that discussion of the issue could harm "community cohesion". Telford's inquiry also identified a "nervousness about race"."
https://theweek.com/crime/the-grooming-gangs-scandal-explain...