Someone knew about this and let it go for some time. it is impossible that the Mossad did not know. what probably happened, the brothers refused to go along with some important person's desires... This is the price they have to pay for refusal... A scandal to expose them and threaten them into action. I suspect organized crime and the Mossad are involved in this.
China pledges to work with Africa in fighting militancy after Mali attack (Reuters)
from the article: Former Mossad chief slams coverage of Ofer Bros affair as 'exaggerated'