The trapdoor was secured with a padlock.
The ladder leading to the trapdoor at Block 85A, Lorong 4, Toa Payoh, was detached.
So how did someone get to the roof above the 22nd storey of the block to vandalise a wall with vulgarities?
In 2011, after a maid was found dead in a rooftop water tank at an HDB block, PAP town councils here said they would spend about $10 million to improve security features to prevent unauthorised access to such structures.
This was after the water agency PUB announced stricter measures to safeguard tanks, such as switching to better-quality locks and further limiting rooftop access.
But someone did it in spite of the enhanced security measures.
He got to the roof and then, standing on a ledge less than 2m wide, used red paint to scrawl his messages.
Even professional painters, who have done work on HDB rooftops, said it was a dangerous stunt.
Working at such heights without safety gear is unthinkable, said Mr Steven Wong, director of P S Resources Pte Ltd.
He added: "We allow workers to work on narrow ledges outside the roof parapet only if there are safety harnesses or gondolas. The risk of falling is too great."
Residents and shop owners were clueless until the police arrived at the scene.
A shopkeeper, who wanted to be known only as Mrs Tan, 60, had opened her shop on the ground floor of Block 85A for less than an hour when the police got there.
She said: "I thought there had been a murder, there were so many policemen.
"I heard it was a vandalism case only later from my first few customers."
So was there a security breach?
Ms Dorothy Cheung, the public relations manager of the PAP Town Councils, said preliminary investigations have found no breach in security.
Earlier reports revealed the enhanced security steps include spot checks, and getting personnel working on roofs to don serialised vests as a form of identification.
Water-tank keys and roof-access keys are also to be stored separately.
But Dr Teo Ho Pin, coordinating chairman of PAP Town Councils, told The New Paper yesterday: "We already have security protocols in place, but authorised personnel may still make mistakes."
The police, which were informed of the incident at about 6.50am, said they are investigating the incident.
The maximum penalty for vandalism is a fine of $2,000 or three years in jail, plus three to eight strokes of the cane.
Residents are hoping CCTV cameras will expose the culprit.
Madam Chan, who lives on the 22nd storey, hopes the vandal will be caught soon.
She said: "When something like this happens, you would feel worried for your own security. I just want him to be caught soon, so I can stop worrying."
Other vandalism cases
Last year, Mohamad Khalid Mohamad Yusop, 34, used red spray paint to mark a cross over the dates at the base of the Cenotaph and wrote the word "DEMOCRACY". He was charged a week later and sentenced to three months in jail and three strokes of the cane.
In 2010, 36-year-old Swiss national Oliver Stricker was sentenced to five months in jail and three strokes of the cane for vandalism and trespass. He and an accomplice cut the fence of SMRT's Changi depot and spray painted an MRT carriage.
This article was published on May 8 in The New Paper.
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