One of many, many versions:

Frankie and Johnny were lovers, O, how that couple could love.
Swore to be true to each other, true as the stars above.
He was her man, but he done her wrong.

Frankie she was his woman, everybody knows.
She spent one hundred dollars for a suit of Johnny's clothes.
He was her man, but he done her wrong.

Frankie and Johnny went walking, Johnny in his brand new suit.
"Oh good Lawd," says Frankie, "but don't my Johnny look cute?"
He was her man, but he done her wrong.

Frankie went down to Memphis. She went on the evening train.
She paid one hundred dollars for Johnny a watch and chain.
He was her man, but he done her wrong.

Frankie went down to the corner to buy a glass of beer.
She says to the fat bartender, "Has my loving man been here?
He was my man, but he done me wrong."

"Ain't goin' to tell you no story. Ain't goin' to tell you no lie.
I seen your man `bout an hour ago with a girl named Alice Fry.
If he's you man, he's doin' you wrong."

Frankie went back to the hotel. She didn't go there for fun.
Under her long red kimono she toted a forty-four gun
He was her man, but he done her wrong .

Frankie went down to the hotel, looked in the window so high.
There she saw her lovin' Johnny a-lovin’ up Alice Fry.
He was her man, but he done her wrong.

Frankie threw back her kimono, took out that old forty-four.
Root-a-toot-toot, three times she shot, right through the hotel door.
She shot her man, ‘cause he done her wrong.

Johnny grabbed off his Stetson. "O good Lawd, Frankie, don't shoot!"
But Frankie put her finger on the trigger, and the gun went root-a-toot-toot.
He was her man, but she shot him down.

"Roll me over easy, roll me over slow,
Roll me over easy, boys, `cause my wounds are hurting me so,
I was her man, but I done her wrong."

With the first shot Johnny staggered; with the second shot he fell;
When the third bullet hit him, there was a new man’s face in hell.
He was her man, and she done him wrong.

Frankie heard a rumbling away down under the ground.
Maybe it was Johnny where she had shot him down.
He was her man, and she done him wrong.

Oh, bring on your rubber-tired hearses. Bring on your rubber- tired hacks.
They're takin' Johnny to the buryin’ ground but they'll never bring him back.
He was my man, but he done me wrong."

The judge said to the jury, "It's as plain as plain can be.
This woman shot her lover, so it's murder in the second degree.
He was her man, though he done her wrong."

Now it wasn't murder in the second degree. It wasn't murder in the third.
Frankie simply dropped her man like a hunter drops a bird.
He was her man, but done her wrong.

"Oh. put me in that dungeon. Oh, put me in that cell.
Put me where the northeast wind blows from the southeast corner of hell,
I shot my man `cause he done me wrong."

Frankie walked up to the scaffold, as calm as a girl could be,
She turned her eyes to heaven and said, "Good Lord, I’m coming to thee.
He was my man, and I done him wrong."