He then went to buy beer from a local shop while his two sons discovered their mother lying lifeless on the floor of the bedroom, it is claimed.
Leonardo, 56, admits killing his wife but claims he should be cleared of murder because he suffered from a ‘loss of control’, jurors were told.
But prosecutor John Price QC revealed Leonardo’s phone had been used to search Google a few hours before the murder.
One read ‘can I survive stab in the eye’ and the other was ‘most painful place to stab someone’, the Old Bailey heard.
Websites related to these search terms were accessed between 2.41pm and 2.46pm.
Half an hour later Leonardo accessed a Camden Council parking permit website.
Mrs Mbombo, who worked as a cleaner, is last known to have used her phone to speak to a friend at 3.52pm.
Both her and Leonardo’s phones stopped being active from around 5pm.
Mr Price said: “Maria Mbombo died in her home at her husband’s hand.
“He attacked her and stabbed her many times with a knife.
“Because of the wounds he inflicted upon her, she bled to death. He was alone with her in their home while that happened.
“The prosecution allege that this is a clear case of murder.”
The couple met in 1988 and move to the UK from the Netherlands in 1990 with their two sons Carl, now 23, and Jacque, 27.
On 18 May this year Jacque returned to the family flat at Chestnut House, Maitland Park Villas, Belsize Park, to find the lights out and the door locked from the inside.
He got no answer despite buzzing and kicking the door and shouting ‘Open the Door’.
Mr Price said Leonardo must have been inside with his dead or dying wife at the time.
Leonardo left the flat an hour later without speaking to his sons and both Jacque and Carl ran inside to find their mother lying on her back on the bedroom floor.
She was wearing a white top and black knickers, her face was purple and she was not breathing.
Paramedics were called at 11.55pm and arrived to find her cold to the touch with rigor mortis in the jaw.
“It was confirmed she was dead and indeed must have been dead for some time,” said Mr Price.
Leonardo, who had cuts to his wrist, was arrested near the Super Choice Convenience Store in Queens Crescent after midnight.
He told officers: “My wife is killed.”
Leonardo, of Maitland Park Villas, Belsize Park, denies murder and perverting the course of justice