On 17 October, 2025, the night of the murder, Pennell had bombarded Phillips with “disturbing” calls and text messages, accusing her of seeing other men.
Feeling unsafe, she asked Keen to come to her address, where they were both ambushed by Pennell.
CCTV footage showed Pennell outside the flats, peering through the spy hole in the front door, before selecting a large kitchen knife, around 8 to 9 inches long.
The prosecution said this was the point where Pennell made “a decision to kill”.
Phillips told investigators she and Keen were in bed when they heard someone fiddling with the lock and “booting the chain off the door”.
She said Pennell “pounced” on Keen and both men began “grappling”.
Phillips said she ran to fetch a neighbour, and when she returned there was “blood all over the walls”.
“Kai was like a demon had taken over his body,” she said. “His face was petrifying.”
Pennell then fled the scene before being found by police helicopters in a wooded area close to the flats a few hours later.
A post-mortem examination recorded a number of stab wounds to Keen’s body, as well as slash wounds on his arms where he had tried to protect himself.
When interviewed by police, Pennell answered “no comment”.
Toxicology reports found no alcohol in his system but levels of heroin, cocaine and methadone were detected, likely to have been from use over the previous 24 hours.
However, the court heard it was “not possible” to know what impact the drugs may have had on Pennell, who was a long-term drug user.