Normal activities were ongoing when the hoodlums invaded the area around 9.05pm on Tuesday.
The gang was said to have attempted to dispose Nnamdi of his mobile phone before stabbing him in the neck and ribs.
It was learnt that residents, who saw Nnamdi lying on the ground in a pool of blood, rushed him to the Ebute Metta General Hospital for treatment.
However, despite attempts by a doctor to rescue Nnamdi, he succumbed to the injuries he sustained during the attack.
Our correspondent gathered that the case was reported at the nearest police station and policemen were detailed to the crime scene.
The state Police Public Relations Officer, SP Benjamin Hundeyin, did not take his calls and had yet to respond to a text message on the incident as of the time this report was filed.