A coroner investigating a crash that killed two schoolchildren has referred it to prosecutors amid concerns a botched police probe enabled illegal tampering with the driver’s phone logs.

Coroner Suzanne Anderson said “serious failings” by officers had potentially handed the opportunity for someone to delete activity on the mobile in the minutes prior to the collision that killed teenagers Debbie Whyte and Nathan Gault.

Devenish College pupils Debbie, 14, and Nathan, 15, were knocked down as they walked along a dark country road near Florencecourt, Co Fermanagh, in November 2008 after being dropped off by a school bus.

Yvonne Seaman, the driver of the Renault Megane that struck them, told police she made two calls to her sister, neither of which were answered, after pulling off the road and parking up minutes before the crash.

But logs of the missed calls were not on her phone when later seized and examined by police.

Ms Seaman, who was not prosecuted over the collision, has expressed her sorrow over the crash but has insisted she never saw the two schoolchildren on the road amid the dark.

Delivering her findings in Belfast Coroner’s Court on Tuesday, Ms Anderson said she had “serious concerns about the lack of satisfactory explanation” as to why the two outgoing calls were not logged on the phone.

Announcing her decision to refer the case to the Northern Ireland Public Prosecution Service (PPS), she said: “It would appear that someone has deleted them (the two calls) and in doing so it would appear that an offence has been committed.”

The coroner was scathing of the police’s handling of the case, listing five crucial errors related to the phone.

“There were some serious failures in the police investigation of the road traffic collision,” she said.

Listing her concerns, Ms Anderson said police did not seize the phone until six hours after the crash.

“This allowed for a period of time for data on the phone to be deleted by someone,” she said.

The coroner said police also did not cut the phone off (isolate it) from its network upon seizing it, thus enabling other texts and calls to be received.

She said that activity could have overridden data related to the deletion of other texts or calls.

Ms Anderson said the police also failed to obtain call connection records from the network provider.

She said an officer had also wrongly recorded the time of the crash as 6.40pm, when it actually happened 30 minutes earlier. That error, she said, “skewed” the police’s subsequent investigation into phone activity.

Finally, Ms Anderson said police failed to interview all those who attended the crash scene or who had been in contact with Ms Seaman following the incident.

As such, officers were unable to determine who might have had access to the driver’s phone in that timeframe, the coroner said.

Ms Anderson said she would send a copy of her findings to the chief constable of the Police Service of Northern Ireland, George Hamilton.

The coroner was presiding over what was a second inquest into the deaths. A fresh probe was ordered by Attorney General John Larkin after the families raised concerns about the first inquest.

Outside court, the family of Debbie Whyte welcomed the coroner’s findings.

As the teenager’s sister Louise and father Colin looked on, family solicitor Matthew McKenna said: “For almost 10 years they have been searching for the truth as to what happened on that fateful night.

“The family has spent a decade campaigning for a proper inquest into Debbie’s death.

“This has involved getting a second inquest where many issues that were not touched upon during the initial proceedings have been ventilated.”

He added: “As the coroner has sent a file to the PPS it is the family’s hope that a proper investigation into the phone activity may yet take place.”

In response to the coroner’s findings, the PSNI acknowledged there were “clear failings” in its investigation.

Chief Superintendent David Moore said: “Our thoughts are with the families today and I know this must be very distressing for them.

“We accept that there were clear failings in this investigation. It will be of no comfort to the families but improvements have since been introduced and we now have a dedicated specialist team to investigate fatal RTCs who support district officers.

“Police investigative capabilities in examining phones and phone records has also greatly improved.

“We will reflect on the verdict made today and determine if further work needs to be done in this area.”