University Police arrested a 28-year-old Cambridge resident early Tuesday morning and charged him with the assault of a Harvard Summer School student in Matthews Hall a few minutes earlier.
Dallas A. Land, a resident of 207 Green St. allegedly attacked a young woman at approximately 3:20 a.m.
Officer John Stanton of the University Police, on duty in the Yard, was alerted by a scream and saw a man running towards the square.
Officer Daniel MacGilvray then saw the suspect running across Brattle and Boylston Streets and pursued him apprehending him at Nini's Corner.
The victim positively identified the man as her attacker. University Police placed Land under arrest, charging him with assault and battery, and took him to Cambridge Police headquarters, where he is being held on $2000 bail.
The victim was taken to the University Health Services, where she received treatment for bruises and lacerations, and was later released.
Police declined to comment on the motive for the assault.