Samples of DNA from a man accused of the murder of Gareth Hutch that were taken when he was arrested for another offence should not be admissible at his trial, his lawyers have argued.
Lawyers for Jonathan Keogh (32), one of three Dubliners accused of the murder, claim there was "no interest" in prosecuting Mr Keogh for the other offence and, therefore, his DNA should not be allowed as evidence.
Judges at the Special Criminal Court will rule on Monday on the admissibility of Mr Keogh's DNA as evidence.
Supt Daniel Flavin told prosecutor Paul Burns that he sought a Section 42 warrant for Mr Keogh last October 12 at Dublin District Court.
There were grounds for suspecting that Mr Keogh had committed an offence in February 2016, other than the offence in respect of which he was being imprisoned, the court heard.
Mr Keogh was on remand in Mountjoy Prison at the time, having been charged last Aug- ust 23 on suspicion of Mr Hutch's murder.
Det Sgt John Healy told Mr Burns that he arrested Mr Keogh at the prison last October 23 for this alleged offence and took him to Portlaoise Garda Station where a mouth swab and fingerprints were taken from him.
He added that Mr Keogh's detention was necessary in order to compare his DNA sample with a mixed DNA profile seized in the case.
There was no link between Mr Keogh and the item seized, the court heard.
Det Sgt Healy told defence lawyer Michael Hourican that he was aware Mr Keogh was charged with the murder of Mr Hutch (36) at the time.
Det Insp Declan Dunne agreed he authorised the taking of the sample, which he believed was necessary to confirm Mr Keogh's involvement in the offence they were investigating.
Mr Hourican told the three-judge court this was a case where there was no interest in prosecuting Mr Keogh.
"Anything that flows from it should not be admitted," he added.
Mr Burns said this was a bona fide investigation and clearly there is an interest in prosecuting this matter as a file is with the DPP.
Mr Hutch was shot dead in the car park of Avondale House flats on North Cumberland Street, Dublin, on May 24, 2016.
Mr Keogh, his sister Regina (41) and Thomas Fox (31) have pleaded not guilty to his murder. The trial continues.