Police said they received four reports between October 20 and 22 involving letters containing white powder at a public library in Yau Ma Tei and the offices of HK01, Dot Dot News and Orange News.
The library received a suspicious letter on October 20. HK01 and Dot Dot News received letters on October 21, followed by Orange News on October 22.
Police said Explosive Ordnance Disposal personnel examined the powder and assessed it as posing no explosive danger. Officers seized it for further testing.