A Kenyatta University graduate was stabbed to death by her lover after breaking up with him in Kahawa Wendani on Monday.
The 22-year-old woman who graduated on July 15, was killed in a rented room in a residential building near Nakumatt Supermarket.
She is said to have had an argument with the man, 36-year-old ex-military officer Maxwell Ochieng, after breaking the news to him.
Ochieng stabbed the woman 10 times in the chest and neck before attempting to kill himself using the same knife.
Police sources said investigators found her body tied to her bed with ropes.
Ruiru divisional police commander Isaac Thuranira and his team controlled a large crowd that wanted to lynch Ochieng.
Police lobbed tear gas canisters and sought the assistance of firefighters in getting into the house as the killer had threatened to harm anyone who gained access.
Ochieng, who had stabbed himself in the stomach, was arrested after a three-hour operation that saw police break the door of the room.
Watchman Evans Silange said he heard noises at about 3am. He said he called police after the attacker threatened him with a knife.
Central region police boss Larry Kiyeng declined to give more details.
Ruiru MP Esther Gathogo, who visited the scene, termed the act as shocking and asked lovers to part ways if they realise they cannot live together harmoniously.
The suspect was taken to Ruiru police station and is to face murder charges.
The body was taken to City Mortuary.