According to the police and Tihar Jail authorities, 63-year-old professor Pental was released from the prison at around 7.30 PM after the High Court's order was communicated to them.
Earlier in the day, a magisterial court had ordered his arrest on a complaint by professor P Pardha Saradhi, who had accused him and his student of plagiarising his paper on biotechnology and publishing it as their own.
He has been accused of cheating and also misappropriating some genetic material from the university's science laboratory.
Even as Pental was taken into custody around 12:45 PM, his advocate moved the High Court for stay of his arrest.
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The matter came up for hearing before Justice S Muralidhar, who stayed the magisterial court's arrest warrant, saying the trial court order is "suspended".
Justice Muralidhar directed Pental to appear before the trial court, when the bail application is listed.
The HC order came on a plea moved by senior advocate Arvind Nigam, representing Pental, alleging that the trial court passed a wrong order and he was illegally taken into custody and sent to Tihar Jail.