Investigators say a 20-year-old woman who had travelled from London died in hospital in Pennsylvania on Tuesday after an injection of silicone.
Detectives said the procedure, believed to have been arranged over the internet, took place at a hotel near Philadelphia International Airport.
They are seeking two people in the matter, the Associated Press reported.
Police said the woman and three companions were staying at a Hampton Inn hotel near the airport after travelling from London.
The woman had the buttocks injection on Monday and a companion had a hip augmentation.
The medical examiner for Delaware County, Pennsylvania, had yet to release autopsy results, and further details of the procedure were unavailable.
Liquid silicone is not approved in the US for cosmetic injections.
— BBC News