Four people have been bailed following arrests made over the shooting of a three-year-old girl in Hanworth Park, Hounslow on Thursday, 20 August.
On the morning of Friday, 28 August, a 16-year-old boy presented himself to a west London police station and was arrested.
Two male teenagers, aged 13 and 14 years, and a 23-year-old man were also arrested in the Feltham area.
All four were arrested on suspicion of grievous bodily harm and have since been bailed to a date in early October.
No weapon has been recovered at this time.
Officers were called by hospital staff on Thursday, 20 August after the child had been admitted with a wound to her abdomen.
The child was playing in Hanworth Park, Feltham with her family. She had been running from her mother to her grandfather when they heard a loud noise which sounded like an air rifle shot. About 30 seconds later the girl started to cry.
The incident happened sometime between 18:00 and 18:15hrs.
The parents and grandfather then realised she was bleeding and took her straight to hospital.
The girl was treated for a penetrating wound caused by an air weapon and underwent surgery to remove the pellet. She has since been discharged.
If you have any information please contact Hounslow CID on 020 8247 6160 or via 101.
To report any information anonymously call Crimestoppers on 0800 555 111.