“It was a scream from hell,” Erik Johansson, who was also staying at the youth hostel, located near Fridhemsplan on the central Stockholm island of Kungsholmen, told The Local.
Johansson said he heard the frightening scream of a woman’s voice around 2.30am early Monday morning.
“It sounded young,” he said.
“But I thought it was just a youngster messing about.”
In reality, however, the screams were that of woman staying at the hostel who was being stabbed repeatedly, prompting another guest to intervene and break up the attack.
“A woman in the room next to me screamed, ‘don’t kill me’,” the good samaritan told the Aftonbladet newspaper.
Police received a call about the stabbing around 2.20am. Following the attack, the victim was taken to hospital with more than 20 stab wounds.
“All I can say is confirm that it happened here,” a receptionist at the STF Fridhemsplan hostel told The Local on Monday afternoon.
According to police, the woman may not have survived the attack had the other hostel guest who overheard the commotion not decided to intervene.
“The neighbour in the room next door heard the scream, forced open the door, and saved her life,” police spokesperson Lars Marklund told the TT news agency.
Despite receiving multiple stab wounds, the woman is in stable condition and is expected to survive.
Police arrived on the scene shortly after the attack and were able to arrest the man who carried out the attack on suspicion of attempted murder.
Throughout the day on Monday, they continued to gather witness statements from guests and staff at the hostel in order to get a better picture of what may have prompted the attack.
According to witnesses, the attacker and the victim were at the hostel together, but it remains unclear what their relationship or the motive behind the attack may have been.
The man who intervened to save the woman, himself a tourist from South Africa, was also forced to fight off the attacker.
However, he refused to take undue credit for his actions.
“She thanked me so many times. But someone had to save her…I don’t see myself as a hero,” he told the Expressen newspaper.