The death earlier this year of former US swimming champion Jamie Cail has been ruled accidental and fentanyl related, according to a Facebook post from the US Virgin Islands Police Department.

An autopsy report from the US Virgin Islands Office of the Medical Examiner listed Cail's cause of death as "fentanyl intoxication with aspiration of gastric content," police said Friday.

Cail, 42, died in February on the island of St. John. Police said at the time that her boyfriend, who has not been identified, left a bar just after midnight to check on her and found her on the floor of their home.

The boyfriend and a friend took her to Myrah Keating-Smith Community Health Center where she was given CPR, authorities said.

Cail, who had previously lived in New Hampshire, ultimately "succumbed to her ailment," officials added, saying she had died on arrival.

Fentanyl is a fully synthetic opioid, originally developed as a powerful anesthetic for surgery. It is also administered to alleviate severe pain associated with terminal illnesses like cancer.

The drug is up to 100 times more powerful than morphine, and just a small dose can be deadly. Illicitly produced fentanyl has been a driving factor in the number of overdose deaths in recent years.

Cail won gold at the 1997 Pan Pacific Championships as a member of the US women's 4x200-meter freestyle relay, according to FINA, the international governing body of swimming. She also won a silver medal in November 1998 at the FINA Swimming World Cup in Brazil in the women's 800-meter freestyle.

USA Swimming said Cail was "a cherished teammate" in a February statement.

As a teenager, Cail spent some time at the Bolles School in Jacksonville, Florida, a private college-preparatory school known as a swimming and diving powerhouse.

Former Bolles swimmer Jooyoung Lee told CNN in February he "never met anyone who had a work ethic like Jamie."

"She was so tough... a serious competitor," he said, noting she would push herself to total exhaustion during training. "But outside the pool, she was a very sweet and sensitive person."

Cail was listed in the top 16 athletes nationwide in her age group in at least 10 events in US Swimming's rankings for the 1996-97 season.

She swam briefly at the University of Southern California before transferring to the University of Maine where she earned a letter in her only season. She graduated in 2003.