Geoffrey Cassidy, Tony Beckham

Retired NFL player Tony Beckham severely beat a peeping tom who was allegedly masturbating outside his daughter’s bedroom window early Monday. “I couldn’t believe it. I was like, ‘Is this for real,'” Beckham told NBC affiliate WESH.

Beckham said he spotted the man, later identified by police as Geoffrey Cassidy, peeking into his daughter’s bedroom window outside his Florida home around 6:40 a.m. Monday.

“I waited for a second and I looked again,” Beckham said. “And I see a white male and he’s standing by my window and he’s trying to get a better position.”

Beckham said the man was looking into the window of his 15-year-old daughter’s bedroom.

He said the man’s pants were partially down and he was pleasuring himself.

“I thought I was getting punk’d,” said Beckham, referring to the prank reality TV show hosted by Ashton Kutcher.

Beckham said he yelled at the man, who tried to flee.

Cassidy was no match for the retired NFL linebacker who still keeps himself in top shape.

“I caught him at the apartment over there and we just had a good conversation,” said Beckham, who did most of his talking with his fists.

Beckham’s wife, Amanda, heard the commotion, came outside and found her husband holding Cassidy on the ground. She called the police.

A jail mugshot shows Cassidy with a black eye and other facial swelling. Cassidy was evaluated at a local hospital for multiple broken bones in his face.

Cassidy was charged with lewd and lascivious behavior with a victim younger than 16 years old. He remains in the Palm Beach County Jail on $1,500 bail.

Amanda said a few hours after the incident, she had replaced the blinds in her home to darker ones so nobody can see through.

“I don’t know if this is his first time coming over here or if he’s been here before or where he’s seen us or how he picked us out, Amanda said. “But it’s scary.”

“I’m sorry that it happened to me. I’m sorry that it happened to him,” Beckham said, adding that Cassidy is “never going to do that again on this side of town.”

“If he was that brave to do it right here, I know this is not the first time he’s done this, “Beckham said.