Aaron Carriere, 21, and Josiah Manful, 20, were both repeatedly stabbed after their car was stopped in Montague Road, Leytonstone, last Saturday.
A gang of hooded attackers surrounded the car leaving Mr Carriere with fatal knife wounds to his neck.
Mr Manful died from fatal stab wounds to the chest.
In total, 11 people have been arrested over the murders.
Five men, aged 18 to 22, were arrested on suspicion of murder on Wednesday while a woman, 46, was arrested on suspicion of assisting an offender. They have been bailed pending further inquiries, police said.
Detectives are still trying to establish the motive for the double murder which happened at about 01:00 GMT, and why the Ford Fiesta stopped in Montague Road.
Another four cars were believed to be nearby at the time of the attack and police say they are keen to identify the vehicles and their occupants.
Det Ch Insp Neil Attewell said: "Someone knows the reason why these two young men were murdered and I am urging those who hold the information not to remain silent but to come forward."
Post-mortem examinations revealed Mr Carriere died as a result of the stab wounds to his neck, while the cause of death for Mr Manful was given as shock and haemorrhaging, as well as stab wounds to the chest.
Five people arrested over the murders of two men found fatally wounded in a car in east London have been released on bail.