The professor was content to feed Mr Poe tidbits of Beale lore, and some, like the flood destroying all the St Louis post offices, well that was truly inspired speculation.
It was similar to his TIME SQUARE days when he had dozens of watches buckled on his arm, all genuine ROLEX's for sale at super low prices, and his big money maker,three card monty.
He could always spot an out of town rube ripe for the pickings, watched that hopeful grow in anticipation of sweeping all that cash from the folding card table, drawing the mark in for that final crushing blow of losing it all.
Those were the days until his missed noticing New York's finest behind him, which resulted in an extended stay at Rikers, where he first heard the Beale treasure story.
After getting out and leaving the Big Apple in the rear view, he did further research on the Beale Papers, and realized that others, maybe not the original 1885 author, made money from crating extended versions of this tale.
He just needed to work his own angle, and the gullible teacher Poe was perfect as his first mark.