At least three Kuomintang heavyweights, including former Taiwan president Ma Ying-jeou, have received threat letters from Hong Kong warning them "not to stop our Hong Kong brothers and sisters from going to Taiwan."

One of the letters, signed by "Ho Fun-hei's team" with Hong Kong stamps, was found by staffers in Ma's office in Neihu district, Taipei, at around 2pm on Wednesday. CCTV footage showed the letter was delivered to the office at 10am that day.

The letter threatened Ma with death if he tried to stop Hongkongers from moving to Taiwan. It also warned the Kuomintang to "be careful what it says" and included the slogan "Liberate Hong Kong, Revolution of Our Times," popularized in the city's anti-fugitive bill movement in 2019.

The letter also contained two pieces of joss paper, as well as drawings of five skulls and three bombs.

Two KMT lawmakers, Lee Guei-min and Lee De-wei, also received similar letters.

Lee Guei-min said she was scared and puzzled when she received the letter, pointing out that the KMT had not advocated stopping Hongkongers from coming.

She also said she should not be threatened for representing public opinion if she did and urged Taiwan's National Police Agency to investigate the incident.

China Television, a pro-China TV broadcaster, also received a letter from Ho's team, which stated the broadcaster should support Hongkongers and not report "bad things."

Initial investigations showed all four letters were delivered from Hong Kong at the same time. Taipei police managed to collect a total of seven fingerprints from the letters but were unable to identify whose they were.

It stated it will seek assistance from Hong Kong police in the investigation and has beefed up security around offices and Ma's home in Wenshan district.

The threats were condemned by politicians from both the KMT and Taiwan's ruling party, the Democratic Progressive Party. DPP lawmaker Cheng Yun-peng said all acts that threaten Taiwan's safety should be punished. Hou Yu-ih, the KMT mayor of New Taipei City, urged police to detect the perpetrators as quickly as possible.

Ho is believed to be Fan, a former member of the now-disbanded student activist group Scholarism. He was active online during the 2019 protests and left for Taiwan subsequently, where he is studying social science at a university.

Ma among trio threatened over exodus to Taiwan