Footage shows the police search this afternoon for the missing girlfriend of the British teenager murdered in Thailand.

Suraphltchaya Khamsa, 16, was the last person with Woramet Ben Taota, 16, before he was found dead in Lampang province on Sunday morning May 7.

The alleged killer Chaiwat Boongarin, 44, was taken on a crime reconstruction this afternoon where Ben's furious father Steven Graham and mother Ooy Taota branded him an 'evil coward' and screamed 'rot in hell'.

However, mystery still surrounds the disappearance of pretty schoolgirl Suraphltchaya, who had the nickname 'Ping Pong', who was seen on CCTV riding a motorcycle with Ben in the hours before he was allegedly bludgeoned to death in secluded woodland.

Sex crimes convict Chaiwat - who was recently released from prison - has refused to give any details of what has happened to the girlfriend, despite repeated interrogations by policemen.

Cops said that more than 30 officers and sniffer dogs from Lampang Provincial Police and the Border Patrol Police had started scouring the woodland on foot and used drones for aerial views.

Police Major General Mongkol Sampawapol, commander of Lampang Provincial Police, said: 'The young girl who was with the victim has not been found.

'The search operation has now been expanded to include the forests and roads within three miles of the nearby villages. We have deployed a drone to capture aerial images to survey the roads and the densely overgrown grove forest from above.

'Officers have been searching since 10am this morning. The phone messages have also been checked and the murderer is being interrogated.'

Video of Chaiwat being taken back to where Ben's body was found shows him telling police which direction he arrived from and how he left. He is seen showing them how he left on a black Honda motorcycle which he later hid with a relative.