A deeply Christian college student in Oklahoma allegedly nearly decapitated the son of a state trooper with a sword because the victim practiced witchcraft, police say.

Isaiah Marin of Stillwater was charged Thursday with first-degree murder in the attack that killed 19-year-old Jacob Andrew Crockett a day earlier.

The two had been playing cards with a third pal, Marin's brother, when Marin removed the 'large black sword' from its sheath and began swinging it around, court records obtained by MailOnline show.

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Devout Christian Isaiah Marin (left), 21, allegedly hacked 19-year-old Jacob Crockett (right) with a sword because of the victim's interest in witchcraft

Crockett, the son of an Oklahoma Highway Patrol trooper, suffered several stab wounds and had his head 'mostly severed' from his body

'I would never cut you, bro,' Marin assured his brother when asked to be careful.

Moments later, the brother told police, he heard 'the sound of someone getting stabbed.'

He looked up and saw blood gushing out of Crockett's chest.

Crockett, the son of an Oklahoma Highway Patrol trooper, suffered several stab wounds and had his head 'mostly severed' from his body. Cops found him lying in a pool of blood.

Marin ran from the scene, sword in hands, and called police from a restaurant parking lot.

'I murdered someone,' he told the dispatcher, according to court records. 'I hacked them to death with a machete.'

Captain Randy Dickerson of the Stillwater Police Department gave a press conference on Thursday to detail the gruesome crime

Above, investigators gather near the home where the brutal near-beheading occurred

He then began 'rambling' about sacrificing and magic.

Police found him fleeing down the street, leaving behind a trail of blood, the sword still in his hands.

A student at Northern Oklahoma College, Marin was described as a 'heavy drug user' and 'religious zealot,' court records show.

He had been watching YouTube videos 'related to his Christian beliefs and the Book of Matthew' just hours earlier.

Marin and Crockett had sparred in the past because the victim had been practicing witchcraft, which Marin saw as contrary to his 'strong' religious beliefs, court records show.

Marin sobbed Thursday as he appeared before a judge via video conference. He is expected back in court on December 1.

Marin is described as a 'heavy drug user' and 'religious zealot'