The stabbings took place at around 1.30am on Saturday outside Alby värdshus, a restaurant in the centre of the town. A 37 year old was killed and five others injured.
The condition of one of the other men is serious but not life-threatening, according to the Karolinska hospital press office in Huddinge. Four of the men received mild injuries.
The suspected attacker was arrested at the scene of the crime and interrogated throughout the day. At around 2pm the prosecutor decided that he should be held on probable suspicion of murder and serious assault.
On Saturday afternoon police confirmed that all of the people involved are residents of Alby or Norsborg.
The motives for the knife attack are still unclear. Police admitted that for one man to stab six was rather unusual, and said they were still unsure of whether there were more assailants.
“We think it sounds a bit odd, but interviews with the injured people haven’t given us much to go on,” said Torvald Ivarsson at Södertorn police, to TT.
Police suspect some form of internal dispute and are continuing to interview the four less seriously injured men. Statements will also be taken from other witnesses to the incident.