Officers investigating an attack on three women at the Cumberland Hotel, W1 on 6 April arrested four people (A, B, C, D) at addresses in Islington on Tuesday 8 April.
A fifth person (E) was arrested in Islington, on Thursday 10 April.
A is a 56-year-old man, B is a 34-year-old man, C is a man (age not known, the previous age given for him was incorrect), D is a 31-year-old woman and E is a 32-year-old man.
All five remain in custody at north London police stations. Warrants of further detention were obtained in respect of A, B, C and D on 10 April.
The four men were arrested on suspicion of attempted murder. The woman was arrested on suspicion of handling stolen goods.
Three women were injured during the incident at the hotel. Victim 1 remains in a critical condition. Victims 2 and 3 remain in hospital, but neither is believed to be life-threatening.