A forensic examination of the mobile phone owned by murdered schoolgirl Anastasia Kriegel may yield vital clues to the identity of her killer.
Senior investigating officers are also hopeful they can recover the killer's DNA from her clothing, which was found close by the battered body of the 14-year-old in a disused farmhouse outside Lucan, Co Dublin.
A post mortem examination of the body, carried out by State Pathologist, Dr Marie Cassidy yesterday, confirmed that Ana had died from blunt force trauma to the head.
The result showed that she had been savagely assaulted with a blunt weapon, possibly a brick, in the farmhouse at Clonee Road, near St Catherine's Park.
Forensic experts are also examining bloodstains found in the building.
Early indications from the post-mortem also show that Ana was a victim of a sexual assault.
Gardai believe she was murdered shortly after she went missing on Monday evening.
The grim find was made at lunchtime on Thursday after an extensive search by Gardai and other agencies in west Dublin and north Kildare.
Officers are now trying to track down friends and social media acquaintances, who had been in contact with Ana either earlier on Monday or over the weekend.
She was last seen alive at St Catherine's Park after leaving her home in Leixlip, Co Kildare.
Gardai have already contacted the families of some of her friends with the intention of taking statements from them to help build up a picture of her final hours.
They have appealed to others, who were in touch with Ana or might have some information of her plans for Monday evening, to contact them at the investigation headquarters in Leixlip, tel 01 666 7800, or on the confidential phone line, 1800 666111.
Investigators are hoping to speak to two boys, aged in their early teens, in the coming days.
Gardai began treating her death as murder after a post-mortem was carried out in the early hours of Friday morning to determine the exact cause of death.
They are now looking into whether Ana may not have been alone at the time she went missing.
An appeal has been made for anyone with any information to come forward. Garda Superintendent John Gordon said the girl's family was "extremely distressed".
A first-year student at Confey Community College, Ana Kriegel was described as a “particularly striking teenager” who was well known within her school and local community. Investigators also said that her family have been left extremely distressed by her tragic death.
Paying tribute after news of her tragic death, the school wrote in a statement; "We've learned yesterday (17th May 2018) of the death of Anastasia Kriegel. May she Rest in Peace. This is a terrible tragedy for the Kriegel family, our school and our community. We are deeply saddened by Anastasia's death. Our deepest sympathy to Anastasia’s family and friends."
Due to the serious nature of the crime, local gardaí are receiving assistance from a number of garda units including detectives from the National Bureau of Criminal Investigation (NBCI).
Her family grew increasingly concerned when she did not return home, and contacted Leixlip garda station at around 8pm on Monday night.
Following a three-day search, her remains were discovered in a derelict farmhouse around 2km from where she was last sighted.
The scene was preserved and the property was examined by members of the Garda Technical Bureau yesterday afternoon.
Gardaí are trying to find out if Ana had made an arrangement to meet up with somebody that evening and are checking out all mobile devices she might have used and looking at her activity on social media on Monday and in the previous few days.
The park where Ms Kriegel was last seen alive is a popular spot frequented by families with children.
The 200-acre site, which was searched by gardaí for three days, stretches from Lucan to Leixlip and the nearby Clonee area.
But just a few hundred metres away towards the Clonee Road, the derelict property where Ana was discovered paints a far bleaker place.
The farmhouse and surrounding property has been derelict for many years, and is a place frequented nowadays only by local youths as a hang-out spot.
Social Democrats TD Catherine Murphy said she has been close friends with Ana’s family for decades. Ms Murphy said she had only spoken to Ms Kriegel’s parents on Wednesday night.
When she wasn’t contactable her parents went to the local garda station almost immediately. “They’re absolutely heartbroken,” Ms Murphy said.
“They didn’t waste any time when she didn’t turn up at home, not communicating with her family was out of character entirely.
“They went to the guards at half past eight. This was just not like her,” she added.
Describing Ana, Ms Murphy said that the young teenager loved dogs and had a tight-knit group of friends. “Ana was tall for her age, but she was a big kid,” Ms Murphy said.
“She loved dogs, she’d have you pestered about what type of dog was this or that.”
Ms Kriegel was also involved in the performing arts, practicing in a dance academy in Leixlip. Last night, State pathologist Marie Cassidy conducted a preliminary examination of the schoolgirl’s remains. Supt John Gordon, of Lucan garda station, said the family are “extremely distressed”.
TD Catherine Murphy said the family are eager for people to share any information they may have and said this crime "needs to be solved quickly".
"We've been personal friends for several decades. We all live in the same area but there is a group of us that socialise together," Ms Murphy told RTE Radio's News at One.
"That's how we know each other, we'd be close personal friends.
"I've known Ana since she was a tot.
"I'd know her from growing up. I wouldn't have seen her all that often because they were very dedicated parents, and their social life changed once she arrived.
"Essentially, I knew obviously from Monday that she was missing."
Ms Murphy said she saw the news of a body being found on social media yesterday.
"I was just utterly shocked you know. You'd be shocked if this was any child, I suppose when you know the family it's just a little bit different.
"Look, you just want to be with the family. You can do nothing in these situations.
"We all felt helpless what could you possibly do, you can do nothing but be there for your friends.
"I would most definitely echo the appeal of helping the guards with any information you may have.
"Ana's family have been nothing but complimentary about the guards. They took them seriously as soon as they arrived at the police station on Monday evening at 8pm.
"She left at 5pm, it was just so out of character, she communicated with them all the time. There wouldn't have been an unanswered text message.
"The family have been very complimentary about the guards and want people with any information at all to come forward.
"This needs to be solved quickly. People in the community are afraid, it's a devastating crime."
Ms Murphy also appeal for privacy for the family.