CHICAGO (CBS) — An argument about a woman using the men’s bathroom along the lakefront last night ended with a Chicago woman’s arrest and her allegations against an off-duty cop, reports WBBM’s Nancy Harty.

Kasandra Bellamy says she was attacked after she – and other women – went into the men’s restroom at 31st Street Beach to avoid the long lines of the women’s restroom.

READ MORE: Chicago Weather: Second Sunday Night Tornado Confirmed; Cool And Clear Monday Night

The 24-year-old therapist says she was at a barbecue with friends and didn’t want to wait.

“There is this guy who says, ‘You’re not supposed to be in here’ and I just kind of brushed him off and I am like ‘Oh, I know’ and I try to walk past him and he grabbed me by my throat and started choking me and he throws me up against a wall,” said Bellamy.

READ MORE: Video Of Gruesome Humboldt Park Shooting From CPD POD Camera Was Made Public Without City's Permission, CBS 2 Has Learned

Bellamy says after she regained consciousness she went to report the attack to police, who arrested her, saying she had assaulted an off-duty police officer, the man from the bathroom.

Bellamy says after being held overnight, she was released. She went to the hospital where doctors said she had a concussion along with bruising and a cut on her face.

MORE NEWS: LIVE UPDATES: 130 Homes Damaged In Tornado In West, Southwest Suburbs As Dangerous Storms Hit Chicago Area Sunday Night

A Chicago Police spokesman says she was charged with battery and is due in court on Aug. 1.