In the Timeless Universe
In the original timeline, Henry Methvin sells out Bonnie and Clyde to Texas Ranger Frank Hamer in exchange for clemency in the Grapevine murders. With the use of Methvin's information, Hamer along with other rangers kill Bonnie and Clyde in their car.
In the altered timeline, Methvin still sells out Bonnie and Clyde, and also confirms Rufus Carlin's innocence. Methvin tells Hamer that he can find Bonnie and Clyde at the cabin near Stortz Plantation. Rufus was able to record Methvin's betrayal with the recording device he carried around for Rittenhouse.
After the betrayal, Methvin goes to the cabin to meet up with Bonnie and Clyde and is introduced to Lucy Preston and Wyatt Logan. Clyde then starts to talk with Henry alone. During Henry and Clyde's talk, Wyatt and Lucy meet up with Rufus. Henry, Bonnie, and Clyde are suspicious of Rufus and therefore grow suspicious of Lucy and Wyatt as well.
Methvin, Bonnie, and Clyde all point guns at the time team, threatening to kill them, but Rufus plays the recording of Henry betraying Bonnie and Clyde. Clyde kills Henry for his betrayal.
Henry Methvin at Wikipedia