Thai police said they arrested an Australian man in his 40s at Bangkok's Suvarnabhumi airport early on Saturday in connection with the killing in Pattaya, about 150 km (93 miles) east of the Thailand capital.
The suspect, identified as Simon Peter Carman, faces charges of murder, concealment of a body, moving or destroying a body, and taking a minor for sexual purposes.
Thai police said they reviewed CCTV footage that showed Carman entering a condominium with the girl, then leaving alone hours later carrying a suitcase.
A still image from security camera footage show the Australian suspect leaving with a black suitcase. Photo by Pattaya police
In a post on its official Facebook page, police said he loaded the suitcase onto a motorcycle and rode to a grassy area near a railway line. Police later issued an arrest warrant and arrested Carman at the airport as he prepared to board a flight back to Australia.
