James Raj Arokiasamy, the alleged hacker who goes by the moniker "The Messiah", was charged in court on Tuesday for hacking into the website of Ang Mo Kio Town Council on Oct 28.
This came even as more suspects were rounded up by the police in connection with the spate of cyber attacks in recent weeks.
Raj, 35, also faces three drug charges committed in 2011. He had been on the run for the drug offences before he was arrested in a Kuala Lumpur apartment on Nov 4 by Malaysian police acting on information provided by their Singapore counterparts.
Raj is also believed to be involved in other cyber intrusions including that of The Straits Times' blog site and the People's Action Party Community Foundation and City Harvest Church's co-founder Sun Ho's websites. He was brought back to Singapore and handed over to the police here on Nov 5.
He is alleged to have carried out the cyber attacks from Dorchester Apartments in Kuala Lumpur. If found guilty of offences under the Computer Misuse and Cybersecurity Act, he could be fined up to $10,000 and jailed up to three years, or both.
Five other suspects have also been questioned in connection with the cyber hacking of the Prime Minister's Office (PMO) and the Istana websites.
Two of the suspects involved in the PMO hacking are brothers and have since been released on police bail. A third suspect in the PMO case is helping investigations.
Two other men, a 17-year-old and a 45 year-old, are being questioned over the hacking of the Instana's website. They have not been arrested.
The police said the cases against Raj and the two other groups of men are not related.
Separately, five other men were charged on Tuesday morning for vandalism of a wall and pavement of a building along Prinsep Link.
They are alleged to have spray-painted wordings - such as "We are one, we are legion, expect us" - said to be linked to the hacktivist group Anonymous, along with a logo "TSK", believed to be a band logo.
The five are: Muhammad Fitri Abu Kasim, 24, Danial Ryan Salleh, 25, Mohamad Fadzly Aziz, 21, Muhammad Redzwan Baskin, 26, and Muhammad Qamarul Arifin Sa'adon, 22.
They were released on bail of $15,000 each and had their passports impounded.
If found guilty, they face jail terms of up to three years or a fine of up to $2,000, and caning of between three and eight strokes.