A witness to the bow and arrow attack in Norway who had been watching Squid Game at the time believed the distressing sounds were coming from the TV show.
Five people have been confirmed dead and several more injured following the horror rampage, reports the Mirror.
Witnesses have described how the attacker open fired inside a Coop Extra store, with the first emergency calls made just before 6.15pm local time.
Sarkis Younan, who lives next to the supermarket, told local media: "I was sitting and watching Squid Game when I suddenly saw and heard sirens.
"I thought it was in the TV series. Suddenly I heard the police screaming like hell: 'Put down your weapon!'"
The 24-year-old student said police entered the store while other armed officers warned residents to remain indoors.
Police arrested a male suspect in the south-eastern mining town of Kongsberg on Wednesday evening following the tragedy.
They say he is believed to have acted alone, with a terror probe launched in the wake of the attack.
The man is said to have been involved in a confrontation with police at the scene and attempted to run away before being apprehended - just over 30 minutes after officers were first alerted at 6.13pm.
Reports claim a responding officer was shot in the back with an arrow.
At least eight ambulances and three air ambulances were seen at the scene.
Oslo University Hospital was put on standby to receive victims.
Town mayor Kari Anne Sand called the incident "gruesome".
She added the area of the attack is Vestiden and has housing, shops and a university campus.
In an interview with VG newspaper she said: "It is a tragedy for all those affected. I have no words.
"This is a shocking event that we did not think could happen in Norway.'"
Squid Game is a South Korean survival drama television series released earlier this month.
Written and directed by Hwang Dong-hyuk, it centres around characters fighting to the death to win a massive cash prize.
