A man was beaten unconscious and was forced to hand over cash and his mobile phone while walking across The Racecourse on Good Friday.
The man was attacked as he walked through the Northampton town centre park at around 1.30am.
The 23-year-old was walking through the park when he was approached by three men, who demanded he hand over cash and his phone.
They then punched him and knocked him unconscious, resulting in him being taken to hospital.
A police spokesman said they were white men, possibly with foreign accents.