A 30-year-old man who was fatally shot on Treasure Island last week was a graduate student at San Francisco State who was days away from receiving his master’s degree in international relations, his professors said.

Yuchuan Guo turned in his thesis paper just two days before his roommates found him dead May 10 in a home on the 900 block of Avenue B. Police said he was killed sometime before 5:30 p.m. that day.

Few details have been released, but Guo’s professors said they were shocked when they learned of his death.

“It doesn’t make sense,” said Sanjoy Banerjee, an international relations professor. “He was a very good and decent person. He just did a lot of good work. He was very diligent, and it’s not believable that some kind of personal motive would have been involved.”

Though the medical examiner identified the victim as Guo Yuchuan, his professors said his name was Yuchuan Guo. He had been studying at the university for two years and had gotten married the year before, said Amy Skonieczny, an associate professor of international relations.

Originally from China, Guo was fascinated with the Chinese national identity and sought to explore the topic through his other passion, filmmaking. Skonieczny said Guo spent a semester interning with a movie studio in Beijing and wrote a report looking at the evolution of the Chinese national identity through film.

“His report was quite pioneering,” Banerjee said “He looked at film scripts over a long period of time and was able to divide Chinese movie history into different parts and observe the different subtexts about national identity in each of them.

“He brought together two scholarly fields, film studies and international relations. In our field, that has not been done very often, and that’s a reflection of so many things on his part. He was intelligent, of course, but it takes a certain amount of courage to tackle a subject that hadn’t been tackled before.”

Guo’s family members, who flew in from China after his death, declined to be interviewed. Skonieczny said the university planned to issue his degree to his family posthumously.

Banerjee said he couldn’t shake the feeling that “we as a university and we as a community have failed.”

“I don’t know what we can do, but this doesn’t feel right,” he said. “We have to acknowledge that he came to San Francisco State, to the city, with a reasonable expectation of safety and we all shared that expectation, and it didn’t work out that way.”

Vivian Ho is a San Francisco Chronicle staff writer. Email: vho@sfchronicle.com Twitter: @VivianHo