The incident which occurred on June 18, involved a seven-month-old girl, who was left with a "small fracture to the skull and a bleed on the brain."
According to a statement issued by police, a wheelchair user allegedly struck out at the baby between 14:00hrs and 15:00hrs that afternoon. The baby was reportedly in her mother's arms at the time.
There were no visible injuries immediately following the alleged attack, but her parents noticed a bump on the baby's head later. They took her to an east London hospital where a scan showed a small fracture to the skull and a bleed on the brain.
After being kept in hospital overnight, the infant was thankfully discharged the next day.
At the moment, officers are trying to determine if the attack was intentional and have so far studied CCTV at the restaurant and spoke with various agencies to identify the people involved.
Detectives are now releasing a CCTV image of a witness they wish to trace - a woman who they believe to be the wheelchair user's carer.
She is described as a black woman, aged approximately 40 years old of large build. She was wearing a beige coloured jacket and carrying a brown handbag.
The man in the wheelchair is described as Asian, aged between 15 and 25 years. His right arm had a foam cast on it. He was wearing a black jacket and was of large build.
Anyone with information is asked to call Newham CID on 07747 780610 or via the police non-emergency line on 101.