A sixth man has been arrested in connection with the fatal stabbing of a 27-year-old woman in Newcastle.
Jodie Wilkinson died in hospital after being attacked by a group of up to 11 men in the city's Stanhope Street on Monday afternoon, police said.
A 25-year-old man who was with her at the time was also injured and needed hospital treatment.
Police said those arrested, a man aged 43, two aged 25, and three others aged 22, 20 and 18, were being questioned.
No-one has yet been charged.
Police believe a group of 10 or 11 men may have been involved in the attack on the pair.
Ms Wilkinson's sister, Amy, described her as "devoted and loving".
She said in a statement: "Jodie would do anything for anyone and we've got no idea why someone would take her life.
"All we ask at this stage is that anyone with any information, no matter how small, please comes forward and assists the police."
A police spokesman said the men arrested on Monday, one aged 22 and two aged 25, were still being questioned.
He said: "Officers attended an address in Queens Court and three men were arrested [on Monday].
"Officers believe there could have been around 10 or 11 men in the group that were involved in the attack on the two victims.
"The weapon used during the offence has not been located and officers are carrying out inquiries to find it.
"We believe this has been an altercation between a group of people who may have been known to each other and not a random attack.
"The attack happened in Stanhope Street and we know it was fairly busy at the time.
"There will be lots of people who were there or who were passing through and who might have seen something. We really need these people, or anybody who thinks they can help us, to speak to us straight away."