"The mother was unable to gain entry into the house since the door was locked," said the father.
Mr Muturi left, only to receive a phone call at around 11am from a friend asking her to go back to Wimbi Court, where the suspect lived in a servant's quarters.
She felt something was wrong when she noticed a crowd and police vehicles.
The father joined her later.
"I could not believe that was my daughter lying on the couch with blood splatted all over on the floor and walls; the place was a mess. My daughter didn't deserve such a gruesome death," said Mr Muturi.
Muthoni's three phones were missing.
The naked body had multiple stab wounds. A postmortem is expected to be conducted today at the Montezuma Monalisa Funeral Home.
Describing his daughter as industrious, Mr Muturi said he was about to open a business for her daughter.
"One of the security guards has told us that the man walked out of the place at around 10am with a small bag," he said.
It also emerged that the suspect called his mother, who leaves in the US, and told her, without elaborating, that he had harmed her girlfriend.
"The mother then called her sisters instructing them to go find out what could have happened. I later learnt they were also at the scene, though I didn't recognise them since we have never met before," Mr Muturi claimed.
The relatives from both sides and neigbours have recorded statements at the Lang'ata Police Station.
Sub-County Criminal Investigation Officer Kipkoech Langat declined to comment on the incident, but assured investigations were in progress.
According to Muthoni's mother, her daughter had known the boyfriend for about one year.
"But their relationship was on and off. They were always fighting and I had advised her to walk away from the man when I learnt from one of her close friends was violent," she claimed.
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The father is appealing to the daughter's boyfriend to surrender.
"It is wrong for the young people to harm each other over differences. If you are in a relationship that is not stable, just walk away because you can't force a person to love you."