Friends Ryan Theobald and Janis Kozlovskis, aged 20 and 17, both died of stab wounds after violence flared in Doncaster town centre in the early hours of January 29.
A 15-year-old boy was arrested last weekend on suspicion of assisting an offender and has been released under investigation as the police probe into the double murder continues.
It comes after Amrit Jhagra, 19, of Cedar Road, was charged with murder in connection with the deaths in February. He appeared before court in April where he pleaded not guilty and a trial was set for July 2022.
Following the stabbings in January, and despite the best efforts of passing members of the public, police and paramedics, Ryan was pronounced dead at the scene.
Janis was taken to hospital via ambulance but later died from his injuries.
Five more arrests have been made in connection to the incident.
In February, a 19-year-old man was arrested on suspicion of murder and was later bailed.
Two men, both aged 41, were also arrested on suspicion of assisting an offender and later released under investigation.
A 17-year-old boy was arrested on January 29 on suspicion of murder and later released on bail, and an 18-year-old man was arrested for a serious public order offence relating to the incident. He has since been released without charge.
Anyone with information which may assist police enquiries is asked to call 101 quoting incident number 135 of January 29, or Crimestoppers anonymously on 0800 555 111.