Philadelphia's acting police commissioner apologized this week after images surfaced of a racially insensitive T-shirt she wore in the 1990s, prompting calls for her resignation.

Christine Coulter ignited uproar when a 25-year-old photo showed her donning a white T-shirt with the words, "L.A.P.D. We Treat You Like a King," written in black.

The shirt appeared to make reference to the brutal Los Angeles police beating of Rodney King in 1991. The encounter between King, who is black, and four white officers was caught on video, but the officers were acquitted at trial, sparking violence, unrest and nationwide protests about racism and police brutality.

Coulter said she didn’t realize at the time that the shirt was an apparent reference to the highly publicized King beating, but said she was "profoundly sorry" for wearing it, nonetheless. She previously said the photo had been taken during a gathering with other officers at the Jersey Shore when she policing the city's 25th district, according to The Philadelphia Inquirer.

"I sincerely hope that a careless decision that I made over 25 years ago doesn't overshadow the work that I've done," Coulter said Tuesday. "I am profoundly sorry for the pain that the shirt and the picture has caused, not to me, but to the city and the communities that we serve."

She delivered the apology during a city council hearing meant to address a report that uncovered more than 300 racist, sexist or biased social media posts by the city’s police officers.

The findings -- published in a report by the Plain View Project, a civil rights watchdog -- resulted in 72 Philadelphia Police Department officers being placed on administrative leave in June. Several other officers resigned shortly after.

Coulter opened her testimony at the pubic hearing by asking for a "few minutes to address concerns" surrounding the controversy. She signaled that the shirt was a gift.

"Although, at the time I didn't recognize the inference, as a police officer I should have and I should have more diligently examined the language on the shirt more carefully before accepting and ultimately wearing that shirt," she said. "When I look at it now, through a 2019 lens, it is clear that it was a bad decision on my part and I would not wear that shirt today."

She said the incident involving King, who died in 2012, "highlighted dark times in policing" and inspired her to work with more fairness and compassion.

Philadelphia Councilwoman Cindy Bass called on Coulter to immediately resign in the wake of the controversy. During the hearing, Bass read excerpts of a letter she said she sent to the city's mayor demanding action.

"It is my opinion it is inconceivable that she was unaware the T-shirt referenced a widely publicized brutal beating of a citizen by officers of the Los Angeles Police Department," Bass said, garnering loud applause from some members of the gallery. "As a law enforcement professional who was not new to the force and clearly recalls the impact that the incident had on policing at the time, I believe that Ms. Coulter was knowledgeable of the inference of the statement."