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While Jared Fogle was only recently arrested, Subway apparently received a serious complaint about the former spokesperson four years ago.

Subway's internal investigation into whether it received prior complaints regarding Fogle's behavior uncovered a complaint from 2011, the company revealed on Friday. The complaint did not point to sexual behavior or criminal activity, according to the company, though it was reportedly "serious."

The complaint in question was filed via Subway's website by Rochelle Herman-Walrond, a former journalist from Florida, reports the Associated Press. In July, following the FBI's raid on Fogel's home that would ultimately lead to him pleading guilty to charges of child pornography and sex with minors, Herman-Walrond revealed Fogle made sexual comments to her about underage girls starting about 10 years ago. Herman-Walrond additionally took her concerns to the FBI, secretly recording phone conversations for more than four years to assist with the agency's investigation of Fogle.

Related: Ex-Subway Pitchman Jared Fogle to Plead Guilty to Sex With Minors, Child Porn

Subway said in a statement that it regrets not properly acting upon or escalating the 2011 complaint and that the company has since strengthened its processes for reviewing customer complaints, comments and inquiries. The company severed tied with Fogle in July, when police raided his home three months after the executive director of the Jared Foundation was arrested on federal child pornography charges.

The sandwich chain alleges that it found no other complaints or warnings of Fogle's behavior while reviewing a million online comments and interviewing past and current Subway employees and management. However, former Subway franchisee Cindy Mills, who once had a sexual relationship with Fogle, says she warned company executives about Fogle in 2008, after Fogle discussed plans to pay for sex with minors. Subway denies a record of these complaints.

Related: From Subway's Jared to Bill Cosby: How Do You Make Hiring a Spokesperson Worth the Risk?