Marvin Ivan "Buck" Barrow (March 14, 1903 – July 29, 1933) was a member of the Barrow Gang. He was the older brother of the gang's leader, Clyde Barrow. He and his wife Blanche were wounded in a gun battle with police four months after they joined up with Bonnie and Clyde. Marvin died of his wounds.
Blanche and Barrow were a criminal twosome similar to Bonnie and Clyde.
Even though he was in a gun battle with police with his wife, it does not mention that she herself is a criminal. I think that the system assumes she was due to her husbands reputation.