A teenage girl was found dead outside an apartment building in Samut Prakan on Thursday morning, the victim of a five-storey plunge.
Police in Phra Pradaeng district were unsure whether Nirada Jodnok, 17, from Khon Kaen, fell accidentally from a balcony next to a stairway on the fifth floor or whether she jumped deliberately.
Her mobile phone and a pack of cigarettes were found on the balcony.
Security guard Thanom Maneerak, 50, found the body at 6am as he was reporting for duty.
A doctor determined that Nirada had been dead for at least four hours.
Thanom said the night guard saw the teenager returning to her room on the fourth floor at 11.30pm Wednesday and heard something heavy fall at 1.30am, but could find nothing amiss.
Tenants said Nirada worked at a nearby convenience store.