(CNN) An Illinois park is investigating after a woman accused one of its police officers of standing by as a man harassed her for wearing a shirt with the Puerto Rican flag, saying it was un-American.

Mia Irizarry says she was trying to celebrate her 24th birthday in the Forest Preserves of Cook County last month when the man approached her asking her why she was wearing the sleeveless Puerto Rico flag shirt, which also had “Puerto Rico” written below the V neckline.
Irizarry recorded the encounter on her phone, saying she felt threatened and posted the video to Facebook. It has since been removed.
On Monday, Forest Preserves of Cook County tweeted that it was aware of the June 14 incident and video.
‏”After the incident, we immediately launched an investigation pursuant to our personnel policies into the response of our officer,” it said, in a series of posts on Twitter. “The investigation is ongoing and the officer involved has been assigned to desk duty pending the outcome. The intoxicated individual involved in the incident was arrested and charged with assault and disorderly conduct.

All people are welcome in the Forest Preserves of Cook County and no one should feel unsafe while visiting our preserves.

— Forest Preserves (@FPDCC) July 9, 2018

In the footage, the man can be seen approaching Irizarry saying: “You should not be wearing that in the United States of America.” He gets closer to her and asks “Are you a citizen? Are you a United States citizen?”
Irizarry can be heard saying that Puerto Rico is part of the United States and the man approaches her multiple times.
Irizarry asks a park police officer to help, saying “I am renting this area and he’s harassing me about the shirt that I’m wearing.”
Later she says: “Officer, I feel entirely uncomfortable, can you remove … please officer” as the officer is seen walking away from her.
Then she says: “Officer, I’m renting, I paid for a permit for this area.. I do not feel comfortable with him here, is there anything you can do? ”
The officer can then be seen talking to the man who gesticulates back and tells him to “shut the f*** up.”