As a tax collector Zacchaeus would have been hated by the Jews. Would Zacchaeus want to be in a crowd of people who hated him?
Later in the first century, Josephus records that when crowds gathered, it was not uncommon for an assassin in a crowd would pull out a long thin and small dagger and quietly stab a person from behind. That assassin could then drop the weapon or otherwise disperse without being noticed and without witnesses.
A group for which this is named is the "
Sicarii" who were a splinter group of the "
Zealots" who had an important part in the Jewish War against Rome that ended in the destruction of the temple in 70 A.D. and the ultimate dispersion of the Jews from Judea.
The Latin word
"sicarius" ≈ "dagger-wielder". From this comes the Spanish word
"sicario" ≈ "salaried assassin" with variants in Italian and Portuguese.