Kochi | Dominic Martin, who had surrendered to police claiming responsibility for the blasts at a Christian prayer meet three days ago, was described as a "brilliant mind" by investigating officers.
He left behind a lucrative job in the Gulf, which left many questioning his motives.
Police had on Monday formally recorded the arrest of Martin who had surrendered a few hours after the blasts on Sunday.
On Tuesday, the Special Investigation Team took Martin to his residence at Athani near Aluva here, where the explosive devices were suspected to have been assembled, in pursuit of crucial evidence.
Over the course of several hours, Martin provided a detailed account of the construction process, using the materials he claimed to have used in the explosion that claimed three lives and left over 50 injured.
When Martin surrendered before the police on Sunday, he had produced bills for the purchased materials, further strengthening the case against him, according to a senior police official.
Bills for petrol purchases linked to the creation of the explosive were among the documents he produced.
Described as a person of "exceptional intelligence and diligence", Martin's decision to relinquish a high-paying overseas position for such a shocking act has confounded authorities.
His proficiency in electronics was taken note of by the police.
Martin, wearing a face-covering mask, was presented before the court on Tuesday.
An application is set to be submitted for a test identification parade at the Chief Judicial Magistrate Court on Wednesday, a procedural step in the legal process.
Despite being offered legal assistance multiple times by the court, Martin insisted on representing himself. He stated clearly that this is his choice, dispelling any notions of financial difficulties.
Besides Section 302 of the Indian Penal Code (IPC) (Punishment for murder) and Section 3 of the Explosive Substances Act, relevant sections of the UAPA have also been invoked against the accused.
The blasts were set off at a convention centre in Kalamassery near here where a prayer meeting of the Jehovah's Witnesses -- a Christian religious group that originated in the US in the 19th century -- was held on Sunday.
Prior to surrendering before the police, Martin had put out a video message on a social media platform claiming responsibility for the blasts and stating his reasons.
In the video, which was aired on various TV channels, the man claimed that he took the decision as the teachings of the organisation were "seditious." Martin further claimed that Jehovah's Witnesses and its ideology were dangerous for the country and therefore its presence had to be ended in the state. He claimed that he had told the organisation several times to correct its teachings, but it was not ready to do so.
"As I had no other option, I took this decision," the man said.
The investigation team is still working to understand why Martin, who had a successful career abroad, would allegedly be involved in the blast. As the case moves forward, more information is expected to come to light.