Malcolm and Louis Garnett were twin brothers born in 1908 in New York City.
Malcolm Garnett became a Broadway theatrical producer whose career was ended by his turn to criminal activities. His last production never opened - a nostalgia musical called "Those Frolicking Forties" - because he was arrested for charges of larceny and assault among others.
His twin brother was just the opposite - Louis Garnett grew up to be an habitual criminal who infused his career with a theatrical bent. As with many notorious criminals before him, Louis Garnett became better known by an alias - Louie The Lilac.
Here's the basic info on Louie The Lilac from the Batman Wiki:
Louie the Lilac was identified by his violet colored suit. He was known to use different lilacs, sometimes mutant breeds, to use against his enemies, such as a flower on his jacket that hypnotized people so he could manipulate them, or his special man-eating lilacs.
Louie tried to corner the flower market and take control of a group of young Gothamites who called themselves the "Flower Children". While most people held the Flower Children in little regard, Louie recognized that they would eventually grow up to be the leaders of tomorrow. So he figured that if he could get in favour with them, he would one day be very powerful and influential. To do this, he cornered the flower market in Gotham City so that he could help them with their flower-in. He was defeated when Batgirl sprayed him with something that caused his suit to grow mold causing him to run into his Hot House.
By 1973, it's possible that the two Garnett brothers were housed together in a Federal prison......