Updated 8.40am

MARK HENNESSY IS a person of interest in a number of unsolved sexual assault cases around south Dublin, TheJournal.ie has learned.

Gardaí are now sifting through messages sent from his social media profiles and liaising with his family in a bid to trace his activities over the last few months.

There are a number of people who gardaí will now want to speak to about his last days.

Gardaí believe Mark Hennessy abducted and murdered Jastine Valdez over the weekend. He was shot dead by gardaí in Cherrywood Business Park in south Dublin on Sunday evening.

Officers are investigating a number of theories as to why he carried out 24-year-old student’s abduction and murder, and Hennessy is now a person of interest in a number of sexual assaults and missing persons cases in south Dublin.

There were a number of cases of sexual assault around the Shankill and Killiney areas of south Dublin in the last two years. Gardaí will revisit these cases in an attempt to ascertain whether there was any link between Hennessy and the attacks.

Sources have, however, stressed that there is currently no solid evidence to suggest that he was behind the crimes. Hennessy was originally from the Cromlech Fields area in Shankill. This is very close to where four of the attacks occurred in the last two years.

Hennessy’s extended family and friends are being questioned by gardaí as officers attempt to figure out why he abducted and murdered Jastine Valdez

TheJournal.ie understands that Hennessy was spotted on Killiney Beach on Sunday morning – the day after he allegedly killed Jastine and hours before he was shot dead during an incident with gardaí.

It is believed he was seen by a friend who had been out searching for him following the release of garda alerts. This person, it is claimed, decided to see if he could track his movements without alerting gardaí.

It is understood that he passed on this information to someone else who knew Hennessy – but not to gardaí.

Hennessy was said to have been in a severely agitated state while on the beach and the person who spotted him was concerned about what could happen if gardaí were to arrive on scene. Despite their best efforts, the person lost track of his location after about an hour.

Hennessy, who was by now wanted for questioning over Jastine’s disappearance, drove the short distance through Ballybrack, where he is originally from, and onto the N11.

Members of the Civil Defence, who were also searching for Jastine, spotted the black Nissan Qashqai at what used to be the Silver Tassie pub on the Bray Road in Loughlinstown and informed gardaí.

Hennessy had been driving on the Cherrywood flyover and was heading towards the M50 when he pulled into the business park.

It was originally believed that Hennessy had left the vehicle and made his way towards the boot where he was seen acting in an erratic fashion. However, a statement released by Gsoc yesterday revealed that Hennessy was sitting in his car when he was shot.

A note apologising for killing Jastine was found in the car. The note also indicated to gardaí where her body could be found. The handwritten words, along with GPS data retrieved from the vehicle’s on board navigation system, helped gardaí track her body.

Anyone with information should contact Bray Garda Station on 01-6665300 the Garda Confidential Line 1800 666 111 or any Garda Station.