Verses with the word searching in the Old Testament (4 verses):

Numbers 13:25
And they returned from searching of the land after forty days.

Job 11:7
Canst thou by searching find out God? canst thou find out the Almighty unto perfection?

Proverbs 20:27
The spirit of man is the candle of the LORD, searching all the inward parts of the belly.

Isaiah 40:28
Hast thou not known? hast thou not heard, that the everlasting God, the LORD, the Creator of the ends of the earth, fainteth not, neither is weary? there is no searching of his understanding.