Three New Haven residents were sentenced on June 29 for the 2015 beating of a 79-year-old Yale professor, the New Haven Register reported.

Kelton Gilbert and Lawrence Minor, both 20, received three years to serve while Aymir Holland, who was 16 at the time of the attack, received two-and-a-half years. Holland’s arrest and subsequent detention sparked protests from New Haven activists, who maintained that Holland stood by rather than participating in the attack.

All three entered plea agreements, as Gilbert pleaded guilty to second-degree assault and conspiracy to commit second-degree robbery. Minor and Holland did not contest the charges, entering pleas of nolo contendere to the same two counts Gilbert faced.

Holland received the lesser sentence because of his age, the Register reported.

The attack occurred as the professor was walking home near the corner of Bradley Street and Whitney Avenue on Nov. 27, 2015. According to the police report, the youths punched, kicked and threw him to the ground and stole his backpack. The professor lost consciousness during the attack.

Superior Court Judge Patrick Clifford said the sentences he imposed must reflect that the incident was “a violent attack on an elderly person for no reason at all except he was defenseless and couldn’t fight back,” according to the Register.

Gilbert, Minor and Holland were arrested the following month by New Haven Police. Holland remained in jail until January 2017, as he was unable to make his $250,000 bail.