Lindsay Lohan has vowed her alleged attacker "won't get away" without being prosecuted.

The actress accused Christian LaBella of assaulting her in her Manhattan hotel room in the early hours of Sunday morning. She alleged he scratched and choked her during an argument about photos she found of her on his cell phone.

Although he was arrested, police later dropped misdemeanour charges of assault and harassment as there wasn't enough evidence. Lindsay is incensed that Christian isn't being brought to justice.

"He isn't going to get away with this," she told New York Post.

"I'm in shock and it was a really scary situation."

The 26-year-old star is reportedly asking witnesses to go to the police.

She met Christian in a nightclub and brought him back to her hotel room to party with some other friends.

The evening soured after Lindsay discovered the images, said to have been taken during the evening out.

Christian works for Republican politician John Shimkus and his family are concerned about the effect the furore could have on his career.

"He doesn't deserve this. It's amazing that her mom said, Thank God he didn't have a weapon of course he didn't have a weapon. He's a good kid, he's worked for two congressmen. He just went to New York for the weekend. Hopefully this doesn't cost him his job," his uncle Peter Jessop said.