A reservoir is being drained as part of the search for the phone of murdered teenager Cameron Reilly (18).
Louth Fire and Rescue Service began helping to drain the reservoir in Dunleer, Co Louth, on Thursday afternoon.
It is beside the field where his body was found last Saturday morning and is understood to hold more than 11 million litres of water.
Fifty members of the Defence Forces are helping gardaí search through the field and undergrowth for a missing iPhone 8 plus.
A Garda spokesman confirmed they have spoken to a large number of people who would have been in his company at times last Friday night into Saturday morning.
He reiterated the message of Garda Supt Andrew Watters, who said people in the vicinity of the incident may have consumed alcohol and drugs but, "that is not the primary concern or the primary focus of this investigation."
Gardaí want anyone with information to contact them in confidence.
Mr Reilly had visible injuries to his neck, but gardaí have not released details on the cause of his death.
Gardaí say the search for Mr Cameron’s phone will continue and they ask anyone who may find it, not to touch it but to contact gardaí. It had a black cover which had a distinctive lime trim.
As part of the search for the phone, it was decided to drain the reservoir. That is expected to be completed on Friday.
Mr Cameron’s funeral will take place on Monday at Saint Brigid’s Church, Dunleer.