When his attackers turned to look at the officer, however, the junior ran.

“I dropped all of my stuff and began screaming,” he said.

The HUPD officer, he said, then chased after his assailants and detained them. Other HUPD officers soon arrived at the scene.

“HUPD response was great,” the junior said.

The Cambridge Police Department eventually sent officers who arrested the men at the corner of Brattle and Story Streets.

The next day, the junior was contacted by the Middlesex County district attorney’s office, which informed him that the suspects had been arraigned for armed robbery.

He was also contacted by a victims’ advocacy unit with the district attorney’s office. This department, he said, helped him keep his name out of the public record.

“We had the judge impound the case files,” he said. “I don’t want the guys who robbed me to know my name.”

The junior explained that he will testify against them in court and, since armed robbery can carry a stiff jail sentence, he is worried about potential reprisal.

The district attorney’s office also agreed to contact him when the suspects post bail.

“The judge issued a low bail,” he said. “But as far as I know, they haven’t posted it.”

The junior said in the future he plans to suspend embarrassment in favor of personal safety.

“From now on, if I’m suspicious, I’m going to act on it. It’s better to be safe than sorry,” he said.

—Staff writer Alex B. Ginsberg can be reached at ginsberg@fas.harvard.edu.