Muhammad Fiqkri Jaffri, pleaded guilty on 7 April to two counts of voluntarily causing grievous hurt to a public servant.
He also pleaded guilty to one count of vandalism, one count of criminal intimidation, and one count of being a member of a secret society.
He had assaulted a policeman with his twin brother and inflicted a traumatic brain injury on the victim.
He was later arrested, and he then headbutted another police officer and broke his nose.
And when he was in the rear seat of a police car, he then kicked the door of the vehicle and damaged it, the resulting repairs amounted to more than $1,200.
His twin brother, Muhammad Farhan Jaffri, was previously dealt with, being sentenced to 33 months and 4 weeks in jail, along with 3 stories of the cane and a fine of $3,500.
The two brothers were drinking from a bottle of whiskey before the incident happened on 23 February 2020.
Farhan then had an argument with his wife at the void deck of Block 755 Jurong West Street 74 at about 4am.
The police then arrived at the scene, including Sergeant Chong Jia Wei, 27, and Staff Sergeant Tity Sumarni Abd Ghani, 35.
Staff Sgt Sumarni asked them if they were alright, and Farhan then hurled obscenities at the policewoman. His brother Fiqkri, who was living in the block, then showed up at the scene.
Fiqkri then aggressively approached the police officers and pointed his finger in their faces, demanding to know what was wrong.
He then told his brother and his wife to go back home and at the same time, gestured at the police and told them to “shut up” and to “zip” their mouths.
Farhan then used vulgarities on Staff Sgt Sumarni and left the scene, before returning a few minutes later and telling his brother that he “did not like Sgt Chong’s face”.
Fiqkri then asked Farhan if he wanted to punch Chong while holding up his fist.
The two men then attacked Sgt Chong, resulting in a serious head injury, and two other officers managed to restrain Farhan.
Staff Sgt Sumarni then used her baton to strike Fiqkri, and instead of cooperating, Fiqkri taunted the policewoman and told her that he was a member of a secret society.
Two more officers then arrived at the scene, including Sgt Chen Jian Da, 28. Fiqkri was then arrested and handcuffed, and he then headbutted Chen in the face.
The two injured police officers were conveyed to the hospital, where Chong spent 2 days in a neurosurgery ward and was given 29 days hospitalisation leave.
Chen was given 5 days of outpatient leave for a fractured nasal bone.
Fiqkri is due to be sentenced on 23 May.