Aaron Ray, who allegedly stabbed Northumbria University student Jason Brockbanks, told a jury he did not know his lover had been seriously injured.
Newcastle Crown Court heard a kitchen knife Ray said he used to defend himself went through a blanket before fatally injuring Mr Brockbanks’ torso.
Read more: Scientific evidence presented at trial of North East man accused of killing student
The 21-year-old said he grabbed the knife after his partner attacked him when he was confronted about his infidelity using the gay app Grindr.
But prosecutor David Lamb KC suggested he had deliberately left the room at Mansion Tyne student accommodation in Newcastle to retrieve the knife from a drawer in the communal kitchen, where Ray admitted putting it when he left.
In cross-examination, Ray repeated his claim that he had fallen on his back as Mr Brockbanks pulled him by the waist after being cut in the attack, contradicting his own claim in police questioning that he had stabbed forwards and downwards.
Wray, who was pressed during the debate with the prosecutor, said: “I don’t know what else to say”, to which Mr Lam replied: “The truth can be good.”
Ray said, “I’m telling the truth. I can only say what I remember.”
He then admitted he may have been wrong about what he initially told police.
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Ray admitted he was holding the knife when it entered Mr Brockbanks’ body, which forensic experts testified was 10cm deep.
Asked how he felt about it, Ray said, “I can’t remember it.”
Mr. Lamb said, “Can’t? Don’t you want to?”
Ray said he left because Mr Brockbanks, his 24-year-old boyfriend of three months, told him to “go away” and he was scared, but Mr Lamb said his departure was “cold and settlement”.
The row between the two men happened on the morning of Saturday, September 24 last year, and Mr Brockbanks’ body was found in the shower cubicle of his room by a member of staff three days later.
Ray, who said he tried to contact Mr Brockbanks and believed their relationship was over, claims he did not know he had been fatally wounded.
But the prosecution say messages sent to friends after a taxi took him home to Sunderland suggest he knew what he had done.
When his friends asked him if he was okay, Ray said that messages like “I can’t tell here” and “I’m in trouble” were because he had woken up his parents.
Ray said he did not know Mr Brockbanks, from Whitehaven, Cumbria, had died until he was told by detectives at the police station.
He told jurors he was “heartbroken” but Mr Lamb suggested his lack of surprise or reaction to police turning up to arrest him at his parents’ home in Sunderland days later meant he knew they will come for him and why.
A day before his arrest, an examination of his devices revealed that Ray, who told the court he was addicted to alcohol, had Googled: “Can schizophrenics be murderers?”
Ray said: “If you go further into my search history, you’ll find tons of similar searches from days, weeks, and months prior.
“People said I was schizophrenic because of what I was seeing. I did my own research. I did not understand what I was suffering from. Now I understand that these are psychoses through alcohol.”
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Mr. Lamb asked, “So that’s your evidence that it’s just a coincidence?”
“It’s just a coincidence that a little over 12 hours before the police come knocking on your door, you Google, ‘Can schizophrenics be murderers?’
“And they arrest you, quelle surprise, on suspicion of this crime?
Ray replied, “Yes, it is.”
He denies murder and the trial continues.