Thai girl weighed only 40kg when she was allegedly murdered by WA man Simon Peter Carman

The 17-year-old girl allegedly murdered by West Australian man Simon Peter Carman weighed only 40kg when she was found dead in a suitcase last week, Thai police say.

The body of Tunchanok Donhomla was found inside a suitcase near railway tracks more than 4km from Mr Carman’s Jomtien apartment complex in the Thai city of Pataya on June 26.

The teenager, known to her friends as Nong Cake, was reported only 40kg and 150cm tall, police chief Colonel Anek Srathongyoo said.

Thai authorities also said the accused killer weighed more than 100kg and stood at 180cm.

Mr Carman was arrested on Friday night, minutes before he was due to board a Jetstar flight bound for Perth. Within hours of his arrest, the teenager’s body was found.

Colonel Srathongyoo has since revealed his name was added to a watch list only 10 minutes before he passed through security and Thai police would have had no warrant to arrest him if he made it through.

Mr Carman, from Perth, is currently being kept at Pattaya Remand Prison.

The teen was last seen alive on CCTV around 3.30am on Thursday entering the complex hand-in-hand with Mr Carman.

He is accused of leaving the rear of the complex dragging a suitcase containing her body about 9.25pm that night. He is accused of strapping the suitcase to the rear of a motorcycle, dumping it near railway tracks, before returning to his complex around 35 minutes later.

Mr Carman faces the possibility of life imprisonment or the death penalty if convicted of four offences — murder, moving or destroying a corpse, concealing a corpse and abduction of a child for indecent purpose.