SINGAPORE - The three cases in the last year of people suffering burns in public areas after sitting on what could be acid may be linked, the police said on Friday.
Commander of Jurong Police Division, Deputy Assistant Commissioner of Police Wilson Lim, added that the police are "determined to bring the perpetrators to justice".
Members of the Government Parliamentary Committee (GPC) for Transport also say they are concerned about the incidents, the latest of which happened on Thursday, and want the SMRT and the Land Transport Authority to investigate.
Chairman Cedric Foo said it was "incumbent upon SMRT" to do so. "It is reasonable for commuters to expect and be assured of a safe ride," he said.
Last March, a 27-year old hairdresser who wanted to be known only as Ms Law claimed her right buttock was burnt by an unknown liquid on a train seat.
On April 17, School of Science and Technology student Aung Phone Naing, 14, suffered second-degree burns on his right thigh after sitting on a "transparent liquid" at a bus stop along Bukit Batok East Avenue 3.
While the substances remain a mystery in these cases, The Straits Times understands that sulphuric acid was involved in the latest case.
The incident left nurse Wan Zahfirah Arshad, 24, with burns on her left buttock after she sat on an MRT seat.
She was treated at the Singapore General Hospital (SGH) and her condition is reportedly stable.
Ms Kalai Natarajan, SMRT's vice-president for corporate marketing and communications, said they are also in contact with Ms Wan Zahfirah to ensure that she is recovering well.
"Passenger safety is SMRT's top priority and we are committed to providing fullest assistance to the police in their ongoing investigations," she added.
Until now, Phone Naing is not sure what caused his burns.
Dr Chew Su Yah, consultant of children's emergency at the National University Hospital (NUH), told The Straits Times that Phone Naing's case was her first case of burns from an unidentified substance.
She said the hospital was unable to find out what the corrosive substance was that he had sat on. The hospital lacked a specimen to conduct tests on as Phone Naing had changed out of his stained trousers, and his wound had been cleaned at a polyclinic prior to his first visit to NUH.
He has been going to the hospital once every three days to get his dressing changed as his wound heals.
He no longer sits down while waiting at the bus stop to go to school. "It's partly because I'm worried," he said.
When told about the latest incident, he said: "Maybe something is going on in this area. It's quite scary. I hope there won't be another incident."
Mr Ang Hin Kee, who is also on the Transport GPC, added that people need to feel assured that there are thorough checks going on.
"If the incidents had involved a child or an elderly person, the injuries could have been more serious."
Get a copy of The Straits Times or go to straitstimes.com for more stories.