JAKARTA • The authorities are investigating allegations that a student at Airlangga University (Unair) in Surabaya, East Java, sexually assaulted multiple people after tricking his victims into performing an act known as "bondage mummification" under the pretence of academic research.

The allegation came to light after a Twitter user with the handle @m_fikris gave an account of his encounter with a man known only as Gilang, who allegedly claimed to be looking for a research subject for his thesis about "wrappings".

The user wrote that Gilang persistently begged him to take part in the research, saying he was at risk of failing in his studies for not finishing his thesis. Gilang was in his fifth year of university.

"I felt sorry, so I agreed to help. He told me that the research subject needed to be wrapped from head to toe so they could show emotions such as anxiety. (At first) I refused, but he convinced me that it was totally safe," @m_fikris wrote.

Gilang sent instructions for @m_fikris and his friend to take turns covering each other's bodies, including their mouths and eyes, with duct tape.

He also instructed them to wrap their bodies in jarik, a traditional Javanese cloth. Gilang asked them to record the process and to send him the footage.

Another victim, who requested anonymity, said Gilang asked him to visit his boarding house to help with his "research" last year. He said Gilang wrapped him in cloth, stripped him naked and sexually assaulted him.

"The incident has traumatised me for the last eight months. I've had nightmares about it," the person said.

Another victim, a 24-year-old, said he had been assaulted by Gilang in 2015, when they were both university freshmen. While he was sleeping at Gilang's boarding house after an event, he said he could feel Gilang cover his body with a blanket and grope him.

"Strangely, I could not move at that time. I suppose he had drugged me. I confronted him the next day, and he admitted all his actions," said the victim.

Unair spokesman Suko Widodo confirmed that Gilang was a student at the university's School of Cultural Sciences and said that the school and the Surabaya police were investigating the allegations.

"We would expel him if he was found guilty as it would be a serious violation," the spokesman said.

THE JAKARTA POST/ASIA NEWS NETWORK