The Last Egyptian by L. Frank Baum

Antar, the sheik, waited for Kāra until his patience was exhausted; then he left the dahabeah and came up through the sands to Fedah to discover, if possible, what had delayed the prince from returning with his promised reward. To Antar this cluster of hovels seemed mean and unattractive when compared with his own village, and these hills were not likely places for treasure tombs. He knew that the French and Italian excavators had been all over them, and found only some crocodile mummy pits.

The sheik grew suddenly suspicious. Kāra's promises were too extravagant to be genuine; doubtless he had deceived Antar from the first, and sought to obtain his services without payment. It was true that Kāra was reputed in Cairo to be wealthy, but he might easily have squandered his inheritance long ago. One thing Antar was certain of -- the Egyptian prince must produce his treasure at once or the sheik, thinking he was duped, would undertake to exact a bit of vengeance on his own account.