A British school janitor will serve life in prison for in the death of his girlfriend after lacing her omelette with sleeping pills.

Stephen Singer was ordered to serve a minimum of 23 years after the judge said he had committed the murder to find a "chilling" solution to a complex love triangle.

Judge Stephen Kramer praised neighbors who tried in vain to save Dina Sharpe, 39, another school worker, who tried to call for help from the window of her fourth-floor apartment.

After breaking down her door, they were only able to rescue a 17-month-old boy from the fire.

Singer, 37, also received a 20-year prison sentence for the attempted murder of that toddler in Sharpe's south London apartment house, and six years for arson.

The court was told Singer was having a 3-year relationship with Sharpe while living with another woman, and things came to a head last summer when the woman found out and threw him out. At the same time, Sharpe discovered that Singer was trying to get back with his long-term partner.

The killer bought sleeping tablets and lighter fuel before going to Sharpe's home. He had ground up the pills earlier in the evening and tried to sedate Sharpe by adding them to an omelette he had cooked for her.

Judge Stephen Kramer said Singer had argued with Sharpe and punched her three times in the face and head, causing brain damage from which she died. He then set fire to the apartment to cover up the crime.

Afterwards, he calmly left the scene and rode off on his motorcycle.

"You are a controlling person who was prepared chillingly to use aggression and deceit to take control of a complex triangle of your own making," Kramer told Singer.

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