The arrestee was identified as Tarequl Islam, son of Rafiqul Islam of Sunamganj Sadar upazila.
Sylhet Additional superintendent of Police Samiul Alam confirmed the matter.
With the fresh arrest all accused of the case have been put behind the bars, he said.
Besides, two suspects- Aynul and Razan were also arrested earlier in the case.
On Monday another accused Mahfuzur Rahman was arrested from Haripur of Jaintapur upazila and the key accused Saifur Rahman, and his accomplices Lashkar, Rabiul Islam and Mahbubur Rahman Roni were arrested on Sunday.
Meanwhile, a Sylhet court on Tuesday placed three accused- Mahbubur Rahman Rony, Rajon and Ainuddin on a 5-day remand each in the case.
Saifur Rahman Saifur, Arjun Lashkar and Robiul Islam, were placed on 5-day remand in the case on Monday.
A group of youths tied up a man and raped his 19-year-old wife at the MC College dormitory on Friday night.
After police rescued the couple, the victim’s husband filed a case at Shahporan Police Station in the early hours of Saturday against nine people mentioning the names of six.
Also read: 3-member probe body over MC College gang-rape