Its diversionary from the 1MDB which was the was the biggest robbery of state assets. To cover and replenish what he and his family members stole, Najib promptly tuned up at China's Belt and Road event and collected their grant/loan. Look at all the corrupt nations that ruined up for grants - Pakistan, Philippines etc. Now the whole country is beholden to China. Its common knowledge that most of these loans will be written off in return for various access and special favours.
These anti-corruption drive will carry on until elections.