Instead, Christian LaBella, 25, and Lohan, 26, filed harassment claims against each other.
The incident happened in a guest room at New York's Union Square W Hotel at 5 a.m., according to a police official who did not want to be named.
Lohan said she and three other friends -- another woman and two men, including LaBella -- went to the room after a night of partying at a nightclub, another police source said. From there, the accounts differ.
Lohan told police she asked LaBella to borrow his cell phone because her battery died, and then discovered photos he took of her at the nightclub, the source said.
LaBella told police Lohan took his phone without permission and refused to give it back.
When she refused to return the phone, Lohan told police that LaBella pushed her onto the bed and she suffered scratches, the source added.
Lohan said she then ran out of the room and into the stairwell with LaBella in pursuit, according to the source. She accused LaBella of choking her during the struggle for the phone, the source said.
Police, who responded to a fire alarm that officers said had been pulled by Lohan, arrested LaBella on two misdemeanor counts of assault and harassment based on Lohan's description of what happened.
Those charges were dropped when investigators decided there was not enough evidence to support them.
Both Lohan and LaBella could have difficulty pursuing competing civil claims, a police source said.
LaBella could argue she took his phone without permission, and Lohan can argue he attacked her, the source explained.
Lohan did not seek medical treatment, the source added.
"While she did sustain some injuries, she was not hospitalized," Lohan publicist Steve Honig said.
Police will have no further involvement in the case.
Lohan, who is on unsupervised probation for a shoplifting conviction, moved to New York this summer.
She was arrested last month after allegedly hitting a pedestrian outside a nightclub and then leaving the scene.
LaBella told police he is a clerical worker from Valley Village.
A spokesman for U.S. Rep. John Shimkus confirmed that LaBella is an employee in the Illinois congressman's Washington office.
"Obviously, the congressman does not condone his actions," said Shimkus spokesman Steve Tomaszewski, declining to comment further.