Police said Friday they arrested a man for allegedly posting a letter on the White House homepage threatening to kill the top US envoy in Seoul, according to Yonhap News Agency.

The 33-year-old, identified only by his surname Lee, is suspected of writing the letter threatening to kill US Ambassador to South Korea Mark Lippert earlier this month, the Seoul Metropolitan Police Agency (SMPA) said in a press release.

After receiving a request for an investigation from the White House, police arrested the man at his home in Seoul on July 14.

On Lee's confiscated laptop, records of access to the homepage were found, as well as a draft of the letter and a screen capture taken as he allegedly wrote the letter on the website, the release said.

Lee denies the charge that he wrote the letter and seems to have no accomplices, the release said.