A four-page letter that Bonnie and Clyde wrote a jailed former member of their gang is going up for auction and could fetch more than $40,000.

In the letter to Theto Raymond Hamilton addressed to the Dallas County Jail, the duo say they should have killed him when they had the chance.

The missive was written in April 1934 in Bonnie Parker’s neat cursive and signed by Clyde Barrow.

They were livid with Hamilton because of a disagreement over how to split $4,000 stolen from a bank.

The letter is being sold next month by Boston-based RR Auction.