Police raided errant Sim Lim Square retailer Mobile Air on Sunday and seized documents and products from the shop.
Eight plainclothes officers were at the shop at about 4pm for more than two hours, The Straits Times reported, citing Shin Min Daily News.
The officers left with four large boxes of documents and products. They also took three computer monitors.
Reporters at the scene also noted that Apple and Samsung mobile phones and tablets were among the products placed in the boxes.
An officer was also seen taking photographs of the store and its products. Other officers went through at least 15 document files and 30 books.
When contacted, the police confirmed that officers were at a mobile-phone retailer at Sim Lim Square yesterday "as part of follow-ups... to police reports lodged" against the store. The police said it was "inappropriate for us to comment further".
The mobile-phone shop has been under fire for the last few weeks over its unethical sales tactics.
Late last month, Mobile Air gave a customer a refund of more than $1,000 in coins. Then, earlier this month, a Vietnamese tourist was scammed by the store and reduced to tears.
The shop reopened for business on Friday after being closed for several days, but apparently under a new owner.
When The Straits Times visited the shop on Friday, its owner, Jover Chew, was not there. Instead, Ricky Lee, 33, who was at the store, said that he had bought over the business and would be reopening it under a different name, HJ Mobile.
Mr Lee said he had bought over all remaining stock at the shop and taken over Mr Chew's lease, which still has about a year left on it.
Mr Lee was present when officers went down to the shop on Sunday, said Lianhe Wanbao. He and another employee were seen speaking with police officers before going into the store's backroom.
He left the shop at about 6.45pm and told reporters that if the police needed his help, he would cooperate.
"Police are investigating Mobile Air. This has nothing to do with me," he said.
Meanwhile, the authorities and Sim Lim Square's management council met yesterday to discuss ways to deal with the errant-retailer problem at the mall, after the council's plea to the Government earlier this month for help with it.
At the meeting, the council shared the challenges faced in dealing with errant retailers and hoped that the laws could be strengthened to mete out harsher penalties to such retailers, the Ministry of Trade and Industry said in a statement.
The mall is also looking into more ways to raise awareness among consumers and inform them about errant stores.
Minister of State for Trade and Industry Teo Ser Luck, who was at the meeting, said it was agreed that "more effective measures must be in place as... unfair business practices cannot be allowed to continue unheeded".
He noted that the management council could implement some preventive measures in the meantime and take a strong stand against errant retailers.
The authorities are also looking at enhancing Singapore's laws and strengthening the enforcement process, he said.
"We urge consumers to continue exercising caution when making purchases, and retailers to be fair and professional."
Get MyPaper for more stories.