A former University of Hawaii mechanical engineering professor who disseminated child pornography over the internet using a file-sharing program is going to prison for more than six years.

A federal judge sentenced Beei-Huan Chao to six years and eight months in prison Monday for transporting child pornography. After he completes his prison term, Chao, 62, will be under court supervision for 10 years during which he must submit to periodic polygraph examination. U.S. District Judge Leslie Kobayashi also fined Chao $35,000.

Chao admitted in May that he allowed someone else to download child pornography video from his computer using a file-sharing program. The someone turned out to be an undercover FBI agent.

He told Kobayashi on Monday that he made a mistake, regrets what he did and accepts full responsibility for his actions. Chao has until February to turn himself in to begin serving his prison term.

His lawyer, Howard Luke, said Chao retired, after working nearly 25 years at UH, shortly after pleading guilty and accepting the fact that he is going to prison. The penalty for transporting child pornography is a mandatory minimum five-year prison term and maximum 20.

The university placed Chao on paid administrative leave following his arrest in August 2016. The arrest came after a federal grand jury returned an indictment charging Chao with one count each of possessing and transporting child pornography.

The federal prosecutor dropped the possession charge in exchange for Chao’s guilty plea to the transporting charge.

Assistant U.S. Attorney Michael David Nammar told Koba­yashi that the FBI downloaded 14 child pornography videos from Chao’s computer in February last year using the file-sharing program. He said the FBI later seized the computer and found more than 500 images of child pornography and 295 images of child erotica.

Nammar said a forensic examination determined that Chao had been downloading child pornography since 2005.