New versions of the “Lennon Wall” have popped up and spread across Hong Kong as citizens have adopted this channel to express their views on the fight against changes to the extradition law – to encourage protesters or express their anger at the police.

Colorful note paper has appeared in unusual places, covering walls outside train stations, bus stops, near a bridge, panels surrounding a construction site, even outside a temple or a shop’s display windows in various districts. These notes have become a way of showing public support to the anti-extradition bill movement.

The Lennon Wall appeared in Hong Kong during the Umbrella Movement in 2014. Protesters wrote messages on democracy and universal suffrage on Post-it notes and stuck them on the wall of a staircase near the Central Government Complex, one of the main landmarks in the area occupied in Admiralty.

However, not everyone welcomed the move. Some Lennon Walls were found destroyed by people who didn’t like them.

At 12.30am on Wednesday, about 100 police in riot gear arrived at the Tai Po MTR Station in the New Territories.

They conducted an operation inside the “Lennon Tunnel”, a pedestrian underpass connecting the Tai Po MTR station and a bus stop.

Officers from the police tactical unit – equipped with helmets, batons, shields and pepper spray canisters. They cordoned off the tunnel, where walls of the underpass were filled with Post-it notes, drawings, photos, and even an item where passers-by could use slippers to hit a photo of officials’ faces.

Police removed any posts that featured the face, name, or identity number of a fellow officer. One policeman came in for heavy criticism after he was seen swearing at protesters during a clearance operation in Mong Kok on Sunday night.

Video clips posted online showed the officer demanding that protesters leave, saying, “F**king remember me, and have a fight with me”.

Police took pictures of notes with the officer’s details on them, then removed them. But other stickers were not touched. The operation only lasted 15 minutes and did not encounter any resistance from the public.

Law enforcers said earlier that more than 800 police officers had filed complaints through a police hotline to say that their personal information had been posted online.

The Cyber Security and Technology Crime Bureau arrested seven men and two women for allegedly accessing a computer with criminal or dishonest intent and criminal damage.

Police appear to be making an effort to protect officers, given the heightened focus on their work. Meanwhile, a video surfaced on social media showing one officer who appeared to be under pressure.

The video showed the officer standing near one of the Lennon Walls in Kowloon Bay holding his phone and saying: “You should complain to the police chief! You should file complain to the higher rank officers, not we, the junior ones.”

“I want to get my dignity back, I can’t find any dignity right now!” the officer yelled at the phone.

An unnamed officer from the top police echelon said recent clashes with protesters had affected some fellows’ emotionally, Ming Pao Daily reported.

He said most of the frontline cops deployed to handle the protest in recent weeks only have about four years experience and were not involved in the operation to manage the Umbrella Movement in 2014.

Given their relative lack of experience, the senior cop said his fellows had performed well, even they were provoked by protesters.

Lam Chi-wai, chairman of the Junior Police Officers’ Association, said police officers had been provoked from the very beginning.

But Lam said the conflict was a political issue that police had been dragged into. He believed the government should solve the problem, not the police.