In 2015, Krishnan started an extra-marital affair with Ms Mallika, who had two daughters from her previous marriages.
In November that year, Krishnan’s wife returned home to see him and Ms Mallika drinking alcohol in the master bedroom.
She used vulgarities against him, and he punched her in the face. When he grabbed a whisky bottle, she apologised as she thought he was going to hit her with it.
Krishnan’s wife subsequently obtained a personal protection order against him. She is still married to him.
He continued his relationship with Ms Mallika, and admitted to hitting her at least once in 2017 over a trivial matter.
The abuse intensified from Jan 11, 2019 after she confessed to him that she had sexual relations with several men, including during the time he was incarcerated in 2018.
On the night of Jan 15, 2019, after one such confession while they were drinking alcohol at the flat, Krishnan kicked and slapped Ms Mallika in the face, punched her in the ribs, and kicked her in the thigh.
As she pleaded with him not to leave, he grabbed her by the neck and pushed her, causing her to fall and hit her head against a wardrobe.
He then pushed her forehead, causing her to hit her head against the kitchen cabinet.
The next day, Ms Mallika sought medical treatment at Khoo Teck Puat Hospital. A CT scan of the brain found no evidence of internal bleeding or skull fractures.
That night, Krishnan and Ms Mallika spoke to her sister on the phone about her relationship with a man.
After the call, Krishnan, who had been drinking throughout the day, started to assault the victim as he felt angry and frustrated at her relationships with other men.
He slapped her, grabbed her by her hair, and punched and kicked her. He then helped her to the bed, and after a while, realised that she was not breathing.
He called Singapore Civil Defence Force at about 1.35am on Jan 17, 2019.
Paramedics responding to the call saw Ms Mallika on the bed with multiple bruises on her limbs and face. She was pronounced dead at the scene at about 1.45am.
Krishnan called his friend for a place to sleep after the assault. He surrendered to the police only at about 1pm that day.