Cape Town – An interview with Guatemalan Diego Novella, shortly after his girlfriend was murdered, came under scrutiny on Tuesday as the Western Cape High Court tasked itself with deciding whether it could be admitted as evidence.Captain Wayne Nachtmann, of the police’s investigative psychology unit, had sat down with Novella at the Camps Bay police station on July 30, 2015.This was after the body of US marketing executive Gabriela Kabrins Alban was found in their room at a nearby boutique hotel.At that stage, Novella had not yet been charged with his girlfriend’s murder and was a "detainee", the court was told.Testifying during Novella’s murder trial on Tuesday morning, Nachtmann described how the murder seemed to be psychologically motivated.Her body was partially naked from the waist down, a hair straightener/curling tong was found by her genitals, there was a chocolate bar on her left thigh and a note with the word "cerote" on her chest.Cerote, a Spanish word, translates to "piece of excrement".When Nachtmann was called to the stand, prosecutor Mornay Julius said he would testify about the interview and "certain utterances allegedly made by the accused".Defence lawyer William Booth objected.Trial-within-a-trialHe said the interview was "nothing more than interrogation which was unfair and unconstitutional".Booth said Novella was not fully aware of his constitutional rights at the time, nor was he properly advised of these rights as a foreign citizen.He also referred to his client's state of mind during the interview."At the time, he was not sufficiently in a sound, sober state of mind."Judge Vincent Saldanha granted a request by the State to hold a trial-within-a-trial, to determine whether the evidence was admissible.Nachtmann’s testimony thus formed part of the trial-within-a-trial. He was not yet allowed to testify about anything Novella had told him during the interview.He testified that Novella was handcuffed behind his back while they spoke."I cannot say whether he was under the influence of anything. The accused appeared normal to me, except he was looking around and adjusting to the environment."Another police officer was in the room, but stood at a distance and observed without saying anything, he said.Fit to stand trialNachtmann showed his police ID and Novella apparently nodded.He said he told Novella that he was there to conduct an interview and he apparently nodded again.He then took out his police-issued field guide, where he had inserted sections of the Constitution.In "simple English", he apparently read him his rights regarding legal representation and visitation."He replied that he understood."Nachtmann said he also got Novella’s permission to record the interview with his cellphone. This was so that there would be no doubt about what was said by either party.Novella, who comes from a wealthy Guatemalan family, has pleaded not guilty to the crime.He was set to argue diminished responsibility due to drug intoxication. He remained in custody at the hospital section of Pollsmoor prison.Psychiatric evaluation by a panel at Valkenberg Hospital found he had criminal capacity and was fit to stand trial.The trial continues.