The police have received information on and are investigating more acts of vandalism by apparent supporters of blogger Roy Ngerng.
Mr Ngerng, a 33-year-old health-care worker, was last week served a letter of demand over a post on May 15 alleging that Prime Minister Lee Hsien Loong had misappropriated Central Provident Fund (CPF) savings.
Last Friday, the police began investigating the defacing of six bus stops after a report was lodged that morning.
"We support CPF blogger" and and "Return CPF money" were scrawled in black block letters across the information and advertising boards at the bus stops, which were around Clarke Quay.
Contractors from the Land Transport Authority are understood to have cleaned up the graffiti by Friday afternoon, but a Straits Times reader spotted two more instances of similar vandalism on Sunday, and reported them to the police.
The latest acts were found on two stone seats along Stamford Road, also emblazoned with "We support CPF blogger" and "Return our CPF money" in black block letters.
The police told The Straits Times yesterday that investigations into the graffiti reported on Friday and Sunday are ongoing.
Those responsible could face up to three years in jail or a fine of up to $2,000, and could also receive between three and eight strokes of the cane.
Speaking to The Straits Times yesterday, Mr Ngerng said he hoped the authorities would engage, rather than punish, the vandals.
"The Government should try to understand, these are not random acts of vandalism," he said.
"There are better ways to express dissatisfaction, but perhaps some people feel as if the Government hasn't responded adequately in the past... Instead of prosecution, I hope the Government will respond to their concerns."
Vandalism has recently hogged the headlines here - just three weeks ago, the rooftop of a block of Housing Board flats in Toa Payoh was painted with profanities directed at the ruling party and the police.
Criminal psychologist Majeed Khader urged firm action to deter further incidents.
"Vandalism could occur for various reasons, such as anger, envy or mischief," said Dr Majeed, who is also the director of the Home Team Behavioural Sciences Centre.
"Sometimes, vandalism may suggest disgruntlement with a target person or society at large... Quick and consistent clean-up and firm actions against the vandals prevent vandals from returning and serve to deter others from imitating them."