At about 8pm on Sunday 4th March a teenage boy sustained potentially life-changing injuries when he was stabbed in Fitchet Close, Langley Green, Crawley.
The police are now investigating the violent incident, and are appealing for witnesses who might have any information.
Three men entered the property in Crawley at around 8pm and attacked another man, who received a serious would in his forearm. This injury is thought to have damaged nerves and tendons and may require surgery.
Two more people, a 51-year-old man and a 47-year-old woman, also at the address, sustained minor wounds.
A 20-year-old man from Crawley was subsequently arrested on suspicion of both money laundering and drug offences. This man has since been released under investigation.
The suspects then left the area in a car, allegedly an Alfa Romeo.
Anyone who witnessed the incident or may have other information relevant to the investigation is asked to contact police online or phone 101, quoting Op Phantom.
Alternatively, please visit the Crimestoppers website or contact the independent charity anonymously on 0800 555 111.