There was a CBN circular last year or the year before that prohibited banks from facilitating crypto transactions on and off their platforms. Since then, Nigerian police changed the narrative that it is banned in Nigeria and anyone involved in it is going against the law. They usually arrest the citizen in question and use it as a means for extortion. I don't know if it's everywhere but around south, it's a norm.
What if the person lied and investigated and noticed he is into cryptocurrencies?
There has been police brutality even before CBN banned bitcoin and other cryptocurrencies. Some people too are actually making their money illegally online and using cryptocurrencies to mask it. Some people also uses other businesses to mask it.