Thai police are offering a reward of more than £13,000 in a bid to catch the killers of University of Essex student Hannah Witheridge.

Miss Witheridge, 23, and David Miller, 24, from Jersey, were killed on the Thai island of Koh Tao on September 15.

Police colonel Kissana Phathanacharoen said a reward of 700,000 baht (approximately £13,300) was now being offered for information which leads to the arrests of the culprits.

DNA samples have been taken from more than eight members of a Thai football team who reportedly threw a late-night party at the nightclub where the victims spent their final hours.

Mr Phathanacharoe said: “We’re working around the clock.

“We’re trying to narrow our inquiries and collect more evidence. We’re encouraging the public who many have information to come forward.

“We’re checking DNA but this is not the only thing we are looking at to prosecute the suspects.”

A post-mortem examination revealed Miss Witheridge, a speech and language masters student at the University of Essex’s Wivenhoe campus, died from head wounds.

A bloodstained garden hoe, believed to be the murder weapon, was found close to where the two bodies were discovered.