Gardaí to trawl DNA database to check if murderer was linked to other crimes
A database containing almost 15,000 DNA profiles of convicted offenders and unidentified suspects in criminal probes will be used to determine if Mark Hennessy was involved in any previous crimes.
The DNA database, introduced in 2014, is used to match crime scene profiles during Garda investigations, as well as identifying missing and unknown persons.
Detectives are expected to use this system in the hope of shedding light on Hennessy, who is the only suspect in the abduction and murder of Jastine Valdez (24).
Gardaí have not yet established a definite connection between Hennessy and any other serious crimes such as unsolved murders and sex assaults.
However, further investigations and searches on the database will be carried out in the coming days to conclusively determine whether Hennessy carried out further depraved crimes undetected.
"The manner in which he carried out the abduction and murder, there are grave suspicions that he has committed a serious crime before. However, this has not yet been confirmed and DNA evidence will help establish if he managed to commit serious crimes in the past without being identified," a source said.
Latest figures for the DNA database show it contains some 14,843 convicted offenders and suspect profiles, 3,978 crime stain profiles, as well as 1,488 elimination profiles. By the beginning of this year, a total of 739 cases had been aided by the operation of the DNA database.
The database was established under the Criminal Justice (Forensic Evidence and DNA Database System) Act 2014, known as the DNA Act, and is an intelligence resource.
One of its purposes is to match a DNA profile from an individual to an unidentified crime scene profile obtained in the course of a criminal investigation or, where there is no match, to eliminate all individuals on the database as potential suspects.
It is also used to assist with identifying missing and unknown persons, including severely ill or injured persons who cannot identify themselves, or unidentified human remains.
The database is being populated with unidentified DNA profiles from crime scenes. These profiles can then be matched with DNA profiles uploaded from individuals under criminal investigation, both convicted and former offenders.
The database is also broken up into two divisions, the investigative and identification divisions. It will be probed to see if Hennessy's DNA has been stored in the crime-scene index, where profiles of persons unknown are collated and stored. This is under the investigation division, and also compromises a reference index of serious convicted offenders, and elimination index of profiles of people who attend crime scenes, such as gardaí.
Hennessy was not known to gardaí for any serious criminal behaviour. However, he had three previous convictions dating back to his early 20s. In 1999, he was convicted of simple drugs possession after being found with IR£100 worth of cannabis. In September 2000, he was charged with a public order offence in Rathmines, Dublin.