Suspect was stopped at Bangkok’s main airport as he tried to fly home.

Thai police have arrested an Australian man over the suspected murder of a 17-year-old girl whose body was discovered inside a suitcase near the resort city of Pattaya.

The man, identified as Simon Carman, 46, was detained on Friday evening at Bangkok’s Suvarnabhumi Airport as he prepared to board a flight to the Australian city of Perth, according to police and local media.

Investigators say security cameras captured the girl entering a condominium with the man in the early hours of Thursday.

Hours later, separate footage showed him leaving the building with a large black suitcase, which he loaded onto the back of a motorbike and rode away.

The girl’s naked body was later found inside the case, dumped near a railway line a short distance from where she was last seen.

Police said she had suffered a severe assault, with heavy bruising to her face.

The alarm was raised when the teenager’s friends reported her missing on Friday afternoon.

Officers traced her final movements to the room she had entered with the suspect, then alerted immigration officials, who intercepted him at the airport.

Carman denies killing her.

Police Colonel Anek Sarathongyu, who heads the Pattaya City Police Station, said officers believed he was responsible and were questioning him on suspicion of murder, adding that he bore fingernail scratches “consistent with a struggle”.

Asked in a video taken after his arrest about marks on his neck, the suspect blamed a spider.

He faces several charges, including murder, concealing a body and taking a minor for an indecent purpose.

Australia’s Department of Foreign Affairs and Trade said it was providing consular assistance but could not comment further.

The arrest comes weeks after Thailand sharply reduced the length of visa-free stays for tourists, following a series of cases involving foreigners accused of drug offences, trafficking and running illegal businesses.