In an apparent Satanic ritual, a Krugersdorp matriculant "with mad eyes" arrived at school on Monday with several swords and allegedly killed one boy before seriously injuring three more people.

The victim was a 16-year-old boy at the Nic Diederichs Technical High School. Another pupil sustained serious head wounds while two gardeners were also stabbed with a 60cm-long sword, said Netcare 911 spokesperson Mark Stokoe.

"Two scholars and two employees at the school were attacked by another scholar who was in possession of weaponry described as being similar to Japanese Samurai swords," he said in a statement.

"One scholar suffered fatal injuries and was declared dead at the scene... the other scholar suffered a serious wound to the head and the other two personnel members suffered slightly less serious wounds." Stokoe said the two gardeners were discharged from hospital on Monday afternoon.

"The gardeners were treated and released, but the other scholar is still in hospital," he said.

The school has not commented on the incident.

According to several people on the scene shortly after the attack, the boy arrived at school with at least three swords and several masks identical to those worn by the heavy metal band Slipknot.

He reportedly told his friends that "today was the day" and tried to convince them to join him in a Satanic-like ritual.

Wearing his mask, he then allegedly started stabbing at boys walking past him, killing one and seriously injuring another, before turning on the gardeners.

At one stage he threw the sword to the ground and his younger brother grabbed it. Teachers then took him to the principal's office.

"Wat nou, meneer? (What now, sir)," he reportedly asked the school principal after the incident, which occurred just before school assembly.

Police spokesperson Captain Jacob Raboroko said he did not resist arrest. "He was very calm when we arrested him in the staff room," said Raboroko, declining to comment on reports that he was high on drugs.

The boy had painted his face black and resembled the drummer of the band Slipknot, said Krugersdorp councillor Alex Raubenheimer.

"He said Satan told him to kill the children," adding that there were reports from witnesses that the boy had abused drugs.

Raubenheimer, who interviewed some of the school children, also said the police had confiscated dagga from some pupils, but this could not be confirmed.

His friends said he was a quiet boy who kept to himself. "They said they all thought he was a nerd," said Raubenheimer.

Another witness was told that the boy spent a lot of time on the internet. His friends apparently said "his eyes looked mad" just before the attack.

Pierre Eksteen, who is in charge of a school support network for children, told reporters outside the deserted school grounds that Satanic music was probably the cause of the attack.

"He came here camouflaged as the guy from 'Slipknot'. We know the wrong kind of music, and drugs have bad effects. Young people need to be informed of the effects of bad Satanic music," said Eksteen.

Another pupil suffered an asthma attack after witnessing the killing.

The police said they found a toy hand grenade on the school's premises but denied reports of a pipe bomb found on the school grounds.

The school, which suspended lessons for the day and did not allow journalists and photographers onto its premises, said it would release a media statement on Tuesday.

Local residents had started laying bunches of flowers outside the school gate.

The matric pupil was in police custody and would appear in court within 48 hours.

Slipknot's debut album, which was released independently in 1996, was called "Mate. Feed. Kill. Repeat". Subsequent albums were released through studio deals.

The band's fourth studio album, "All Hope Is Gone", is set to be released this month.

Sapa