The head, probably belonging to man in his 40s, was put in a plastic bag and hung from the bridge's railing. It was found at about 2pm. A doctor estimated that he had died for at least eight hours.
Two sentences, "I want but I cannot...," and "I came to Bangkok to be you," were found written on the bridge's railings.
Pol Col Chavalit Prasobsilp, a police chief, said that it was apparently not a suicide and he will wait for autopsy results before concluding how the head was cut from the body.
"We will check the security circuits at the bridge and see if anything related to the incident was captured," Chavalit said.
"We need to urgently know who is the victim," he said, requesting that the media published clear pictures of the victim's face to help police identify the victim.
