Dr. Joel Watts told Magnotta's murder trial Tuesday he would have liked to speak to both individuals but was unable to get any solid information on how to track them down.
Magnotta, 32, has pleaded not guilty to the slaying and dismemberment of Jun Lin in May 2012.
While Magnotta admits having caused Lin's death, Watts and another psychiatrist have testified he was psychotic the night of the killing and was incapable of telling right from wrong.
One of the people Magnotta described to Watts was a woman named Rebecca for whom he housed a python that was central to an infamous online video that showed a cat getting killed.
The second person he frequently talked about was an American called Manny, who Magnotta says allegedly treated him violently after they met in 2010.
In the version of Lin's slaying Magnotta gave to Watts, Manny suggested to the accused that Lin was a government agent sent to kill him.
Magnotta then reportedly heard other voices telling him to kill the Chinese engineering student.
The Crown said Magnotta's version of events as given to Watts doesn't tend to match what was captured by video surveillance at the apartment.
Magnotta is not able to say with certainty at what time Lin was killed, but Watts believes Magnotta's version is reliable.
He cautioned against trying to match Magnotta's memories with the video evidence the jury has seen, saying it isn't uncommon for people suffering from psychosis to have a disjointed chronology of events.
"Mr. Magnotta is not recounting his account of exactly what happened on a moment-to-moment basis based on the time log of those videos," Watts said.
Magnotta told the psychiatrist that at times he couldn't remember if his recollections were memories of the actual night or memories of Lin's dismemberment video that he saw later with his lawyer, Luc Leclair.
Watts said it also remains unclear if either Manny or Rebecca actually exists. In the case of the latter, Magnotta said he didn't know her family name.
Watts testified that while Manny may be a real person, Magnotta's experiences of him appear to be driven by hallucinations. As for Rebecca, Watts conceded that "I guess you can say that I don't know if she's real or not."
On Tuesday, the Crown peppered Watts with questions about the night Lin died. In some instances the psychiatrist didn't broach specific topics with Magnotta during their meetings. In others, the accused could not remember.
For example, Watts didn't ask why a suitcase containing Lin's torso was slashed, spray-painted and fitted with a lock because it was a detail that escaped him.
Watts said Magnotta couldn't say why he threw away the camera used to film Lin's slaying as well as to shoot video of a mystery man one week earlier.
Magnotta also couldn't recall a video recording of him holding an electric saw near the head of that man, Watts said.
In addition to first-degree murder, Magnotta is also charged with criminally harassing Prime Minister Stephen Harper and other members of Parliament; mailing obscene and indecent material; committing an indignity to a body; and publishing obscene materials.
The Crown is arguing the crimes were planned and deliberate.
Watts returns to the stand Wednesday.
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