There is growing concern about cybercrimes like romance scams and sextortion targeting victims around the world. Hiding behind fake or hacked accounts, fraudsters bombard their targets with messages in the hope of extracting money or compromising personal information. In Nigeria, these operations are often honed in dedicated training academies. Known as 'Hustle Kingdoms', they help con artists stay up-to-date with the most effective techniques for carrying out digital fraud. BBC Trending explores how these schools operate, both in person and on social media, to train the next generation of scammers.