After three days waiting beside the ninth, 10th and 11th locks of the Grand Canal in Clondalkin, the strain is taking its toll on the young man's parents, Marie and Alan White.

They spend almost all of their time sitting in the family car, watching and waiting for a signal from the divers. This signal, given once last Wednesday, spelled the end of 18-year-old Shane Coughlan's life, but it had at least returned him to his family.

"How long more is it going to take? When are they going to find him?" are the words on everyone's lips, as the crowd, made up almost entirely of teenagers, follow the garda� wearily from lock to lock. No one believes David White is still alive.

It is a week today since both young men were last seen alive, at a Saturday-night house party in the Lindisfarne Estate in Clondalkin.

At 4.30 in the early hours of Sunday morning, the friends decided to go to the local 24-hour Esso station for cigarettes and phone credit.

When they failed to reappear, everyone assumed that they had gone home. But when they hadn't reappeared by Sunday afternoon it was clear something had gone amiss.

The Esso station is right beside the ninth lock of the Grand Canal and when garda� found a Timberland boot believed to have belonged to David at the water's edge on Tuesday evening, a fullscale search of the canal was launched.

White, an apprentice painter from Carrickmore Avenue, Citywest, was the eldest of three children. Coughlan, or 'Cocko' to his mates, was from Millpark in Clondalkin and the younger brother of Sheffield Wednesday football player Graham Coughlan.

It took just a few hours to find Coughlan's body, not far from where the shoe had lain on the bank. But as the searching recommenced, and went into a second day and then a third, questions were asked as to where David White could possibly be.

"They were such lovely boys, " said a family friend. "The families are shattered and the longer it goes on for David's parents the worse it gets. It was a tragic accident. Surely that's all it could have been."

A post-mortem on Shane Coughlan's body revealed he had died from drowning and, so far, garda� say no foul play is suspected. At the banks of the canal, the boys' friends believe that one must have fallen in and the other jumped in to save him.

However, David's father, Alan White, has said his son called his younger brother at 6.30am on Sunday. The call was not answered and no message was left.

Does it mean the boys hung around together for a couple of hours before entering the canal? Or did White call his brother because he was in an emergency situation? Everyone has unanswered questions as they stand in the rain and watch garda divers search the canal, but there will be no answers until White's body is found.

"We're just going to wait here, " a friend of White's, one of the many teenage girls huddled together, says. "We're not going anywhere till they find him." Young couples cuddle together in the cold, the girls crying into their boyfriends' shoulders, the young men staring at the ground. They have lost two friends.

"Cocko and David, I'll miss you loads. You were a friend for life, " reads a card on one of the many bouquets of flowers strewn around the ninth lock.

As the crowd bends over the bridge to watch the progress of the divers, a poster of the two boys comes into view. Dressed in tuxedos for the debs ball they attended just last autumn, they look impossibly young and happy.

"They keep describing them as men in the papers, " says a young girl. "But they weren't men. They were only young."

When a garda approaches Alan and Marie White, the crowd parts respectfully. But there is no news, just another part of the canal to be searched.

With hunched shoulders, they get back into their car.

The crowd also moves to their cars and drive in convoy to the 10th lock. More searching, more waiting for the signal that is now so desperately needed. David White's family needs to bring him home.

A lone garda is left standing by the ninth lock. On a wall hangs a plaque, dedicated to the two boys who drowned in that very spot 10 years ago.

"In Loving Memory of our sons Keith Mahon and Jason Ryan who lost their lives in the ninth lock on 29 May 1997, " it reads.

"Dearly loved, never to be forgotten."