The family of a 15-year-old girl found murdered in woods say they are "shattered".
Rebecca Aylward, from Maesteg, near Bridgend, was found in woodland near Aberkenfig on Sunday.
She died of head injuries, and South Wales Police have been granted an extra 36 hours to question two boys, also 15, arrested on suspicion of murder.
In a statement her relatives said: "As a family we are all devastated. Becca can never ever be replaced."
Rebecca was last seen in Sarn Hill, Sarn, near Bridgend, at about 1230 BST on Saturday. She had been dropped off by relatives to visit a friend but failed to return home.
Detectives said they needed to speak to anyone who saw her subsequently.
A post-mortem examination has taken place and the cause of death was found to be as a result of head injuries.
The 15-year-olds who have been arrested are in police custody.
In a statement issued via South Wales Police her family said: "Rebecca, also known as Becca, was dearly loved by all her family.
"She will be sadly missed, she was a very happy young girl, she had an outgoing and bubbly personality.
"She was very motherly towards her younger brother and sister who absolutely adored her; they have been left devastated by her death.
"She had a wide circle of friends and was popular and well liked by all who knew her.
"All the family have been shattered by her death.
"As a family we are all devastated by her untimely death and wish to be left alone to deal with our grief in private.
"Becca can never ever be replaced."
Chief Supt Carl Davies said: "This is a tragic incident and my heart goes out to Rebecca's family at this difficult time.
"This will no doubt be a huge shock to the local community. A thorough and professional investigation will continue.
"I know the community in this area is extremely close knit.
"My appeal today is for anyone who has any information about Rebecca's whereabouts during the key times to contact us.
"As a police service we will utilise our extremely strong community links to piece together every snippet of information.
"Please speak to us if you have any information, no matter how small."
A help and advice line for anyone affected by the death has also been set up on 01656 724057.
Rebecca was a pupil at Archbishop McGrath Catholic High School, which said it was "deeply shocked".
Father William Isaac, in a statement for Rebecca's school in nearby Tondu, said: "We are all deeply shocked and saddened by what has happened.
"Archbishop McGrath Catholic School is part of our larger Catholic family.
"Our love, thoughts and prayers go out to Rebecca and her family and friends at this very sad time.
"We are co-operating with all the agencies, including South Wales Police and Bridgend council, to provide support to all those affected by this great tragedy."
Derek Lewis, who lives near the edge of the woods, said the spot was a popular gathering place for youngsters.
Mr Lewis, 52, said: "I've been living here 40 years. It's a regular place for youngsters to be. I've seen youngsters [aged] 10, 15 years going in there when it's dark.
"They get boisterous, but we've never had trouble. You can hear them laughing."
His sister Denise, 46, described how police arrived at the scene on Sunday morning.
She said: "There were helicopters right over the top of us. We were in the garden and everything was going on.
"We saw all the police turn up. They were stopping traffic up the lane. Then the police were in the woods. It's really sad."
Local councillor Phil White called the teenager's death "shocking and sad".
He said: "My thoughts go out to the family, this is devastating for them.
"This is a small community and the community will be choked hearing this news this morning."
Anyone with information is asked to contact the incident room at Bridgend Police Station on 01656 679585 or Crimestoppers anonymously on 0800 555 111.