A teenage girl was brutally assaulted for about 12 hours, leaving her with a fracture in her spine and extensive soft tissue injuries that led to kidney failure.

The three men then abandoned the battered 16-year-old girl at the void deck of a block of flats where good Samaritans stepped in to help her.

One attacker, Aminnuddin Siregar Aminullah Siregar, 32, was sentenced to 10 years' jail and 12 strokes of the cane yesterday.

He pleaded guilty to two counts of using a weapon to cause grievous hurt to the girl and a criminal intimidation charge. He also admitted to two drug consumption charges.

The cases involving the two other alleged attackers - Muhammad Khalis Khairi, 27, and Rushdi Rusli, 28 - are still pending. The girl was Aminnuddin's friend and she cannot be named due to a gag order to protect her identity.

The court was told that at around 7pm on April 20 last year, Aminnuddin asked the girl to come to his flat on the ninth storey of a block in Telok Blangah Crescent as he was still unhappy about a dispute between them earlier. Court documents did not reveal details of the dispute.

He scolded the girl when she turned up before using a 75cm-long metal pole to hit her.

Deputy Public Prosecutor Kumaresan Gohulabalan said: "When she attempted to leave the unit, Aminnuddin pulled her back into the living room. Aminnuddin also punched, kicked and slapped her during this ordeal, which lasted about an hour. There was no one else in the house at this time."

Rushdi and Khalis arrived at 10.30pm at Aminnuddin's request and they allegedly joined in the attack, using the pole to hit her. The men would also drag the girl back to the living room whenever she tried to leave the unit.

At one point, the girl ran to a bathroom, locked herself in and tried to shout for help through a window. When she stepped out, Aminnuddin placed the tip of a knife at her neck and said: "If you don't shut up, I will kill you."

Weakened after her beating, the girl slumped onto the floor. DPP Kumaresan said: "Aminnuddin then said to Rushdi that they should just throw her down out the window. Aminnuddin and Rushdi attempted to lift her body off the ground but were unable to do so."

The assault continued until around 7am the following day before the men took her to the void deck of the block.

After passers-by stepped in, she was rushed to the Singapore General Hospital and was in the intensive care unit for three days.

Police arrested Aminnuddin on April 22 last year and his urine was found to contain traces of methamphetamine. He absconded after he was charged in court and had a warrant of arrest issued against him.

Officers managed to track Aminnuddin down and he was re-arrested in a Geylang hotel on Dec 12 last year. He failed another drug test when methamphetamine was detected in his urine for the second time.