The driver of the cement mixer truck involved in the accident which killed two brothers in Tampines is "very traumatised" by what happened.

"He is actually resting at home because he is very traumatised," Mr Philip Lu, senior general manager of G&W Ready-Mix, told The Straits Times Wednesday evening.

The police said the driver was released on bail on Wednesday and is still assisting investigations.

The truck involved in the accident belongs to G&W, but the driver is from a transportation company called Hi-dynamic.

This is a sub-contractor of G&W and helps to operate the cement company's bigger vehicles. These trucks are used to deliver concrete to construction sites.

Mr Lu did not want to say where the truck was heading to when the tragedy occurred. He also didn't want to comment further as police investigations are ongoing.

The driver is understood to be a 56-year-old Singaporean.

Student Nigel Yap, 13, had gone to fetch his brother Donavan, seven, from school when their bicycle was hit by the truck at the junction of Tampines Ave 9 and Tampines Street 45 at about 5.40pm on Monday.