The pick pocket was brandishing a knife.

Using : take, hold, or deploy (something) as a means of accomplishing or achieving something; employ.
Pointing : the action of filling the joints of brickwork or masonry with mortar.
Showing : the action of showing something, or the fact of being shown.
Waving : move (one's hand or arm, or something held in one's hand) to and fro.
Brandishing : wave or flourish (something, especially a weapon) as a threat or in anger or excitement.

Synonym of Brandishing is Waving