Rothwell was last seen leaving Chili's Restaurant in Clearwater, Florida at 3:38 p.m. on March 21, 2011. She had had lunch with a female friend and told her she was going home to tell her boyfriend, David Robert Perry, that she was moving out and wanted to end their relationship. Rothwell lived with Perry in the 2700 block of Gulf Boulevard in Indian Rocks Beach, Florida. Rothwell had plans to meet friends that night, but she never showed up and has never been heard from again. The day after she disappeared, her 2007 Green Subaru Outback with the Florida license plate number DJE4D was found parked at 2nd St and 4th Avenue in Indian Rocks Beach, about two miles from her home. Her purse and wallet were missing.

Rothwell was a cadet attending the Pinellas Police Academy at the time she went missing; Perry is a retired New York State corrections officer. Authorities described their relationship as "volatile." According to one of Rothwell's friends, Rothwell had described Perry as possessive and controlling and said he'd been reading her emails. Sometime between 4:30 and 5:30 p.m. the day Rothwell disappeared, her downstairs neighbors heard loud pounding and banging coming from her condominium, as if a large object or objects had been dropped or thrown. They then heard the sound of the vacuum cleaner running in the master bedroom. The neighbors were afraid of Perry and had once filed a police report against him.

When police checked Perry and Rothwell's condo, they found it in a "pristine, sterile" condition. Some of Rothwell's notes from her police academy classes turned up in the garbage, which is uncharacteristic of her behavior. Perry left town for New York on the night of Rothwell's disappearance and, shortly thereafter, began a new relationship with another woman. He hasn't cooperated with the police in her case. In May 2011, Perry was arrested and charged with grand larceny and insurance fraud in an unrelated case; he allegedly fabricated an injury on the job in 2003 and claimed worker's compensation. In August 2011, he was officially identified as a suspect in Rothwell's disappearance.

Rothwell was raised in Maryland, attended college in Colorado and worked as a human resources employee for a hotel before she joined the police academy. Prior to her disappearance, she had never missed a single day of class. Her loved ones said she was looking forward to the career change and would not have left of her own accord. Her case remains unsolved and foul play is suspected.