Stephen Silver's barrister has told the jury at his trial for the capital murder of Detective Garda Colm Horkan that it would be "highly unsafe" to find him guilty.
Mr Silver, of Aughavard, Foxford, Co Mayo, claims he was suffering a relapse of a mental disorder at the time he shot him in Castlerea, Co Roscommon in 2020.
Stephen Silver accepts responsibility for the death of Detective Colm Horkan but the jury will have to decide what level of responsibility he should be held responsible for.
The trial heard extensive evidence in relation to his seventeen admissions to psychiatric hospitals over the years, the majority of which were involuntary.
In her closing speech, his barrister, Roisin Lacey SC, said he doesn't suffer from a personality disorder.
She told them it was more probable than not that he was suffering a relapse of bipolar affective disorder and was in a manic state of what she described as this serious mental illness at the time.
Furthermore, she accused the prosecution of not disproving that beyond a reasonable doubt.
She also said there was no formal proof presented in relation to Colm Horkan's membership of An Garda Síochána and claimed "certain discrepancies" in that regard have gone "unexplained".