Activists have asked the US to impose targeted sanctions on senior leaders of the Ugandan police force, following the brutal arrest of a lawyer representing opposition presidential candidate Robert Kyagulanyi aka Bobi Wine.

Ugandan police on Tuesday arrested Mr Nicholas Opiyo, a human rights lawyer and Executive Director of Chapter Four Uganda. Mr Opiyo was at a restaurant with four other lawyers when he was reportedly blindfolded and bundled in a car by plainclothes officers.

A spokesperson for the Ugandan Police Force said Mr Opiyo was being detained for money laundering crimes. But Robert Amsterdam, Wine’s international lawyer, argued there is a political motive to dissuade the lawyers from investigating recent police killings.

“Such thuggish scare tactics and trumped up charges are aimed at discouraging the investigation being led by these lawyers into the police killings of 37 protesters on the 18th and 19th of November.”

The protests arose after Mr Kyagulanyi who is running for Presidency on the National Unity Party was arrested and detained. Mr Opiyo and his colleagues were reportedly investigating individual police officers involved.

Mr Amsterdam, who also represented Tanzanian opposition figure Tundu Lissu and Cameroon’s Maurice Kamto, said the US must punish the rogue police to stop what he argued was ‘thuggish’ treatment of opposition figures and activists.

“This action by the regime of President Yoweri Museveni represents a clear and unambiguous attack on the democratic rights of the Ugandan people,” Amsterdam wrote in a letter to Elliot Engel, the Chairman of the US House of Representatives Foreign Affairs Committee, and Michael McCaul the Lead Republican of the House of Representatives Foreign Affairs Committee.

A spokesperson for the Ugandan Police Force said Mr Opiyo was being detained for money laundering crimes.

“We would like to confirm the arrest of lawyer Nicholas Opiyo by a Joint Task team of Security and Financial Intelligence, on allegations of money laundering and related malicious acts,” the police said in a statement on Tuesday evening.

“The investigations are progressing well and any new developments will be communicated in due course. He remains in our custody at the Special Investigations Division.”

Amsterdam’s letter to the US Congress asked for sanctions usually imposed on individuals under a law known as the Global Magnitsky Act. Passed in 2016 during the Obama administration, the law may allow the President to revoke US visas and block all US-based property and interests of foreigners and foreign organisations. Usually that happens to those deemed to have violated human rights through extra-judicial killings, torture or any ill treatment of individuals who expose illegal activities of government officials. It may also target corrupt officials.

Last year, the US Department of Treasury imposed sanctions on former Ugandan police chief Edward Kale Kayihura “for using corruption and bribery to strengthen his political position, as units under his command committed serious human rights abuses,” when he was head of the Uganda Police Force (UPF).

Kayihura was police boss between 2005 and 2018 where he masterminded brutal arrests of former opposition candidate Kizza Besigye. Kayihura is currently facing charges related to crimes against the state.

The arrest of Mr Opiyo and four of his colleagues—Herbert Dakasi, Anthony Odur, Esomu Obure and NUP's Human Rights Officer Hamid Tenywa—aroused criticism both in Uganda and abroad. Natalie E. Brown, the US Ambassador to Uganda, said it was worrying to hear of his arrest.

“I just met Opiyo and was impressed by his commitment to rule of law and to uplifting his fellow citizens,” Ms Brown wrote on her Twitter page, referring to a recent meeting she had in Kampala with Mr Opiyo, leaders of the Uganda Law Society and other human rights activists.

“News of his arrest is troubling and I call on the Ugandan Government to ensure his safety and wellbeing. Civil society must be able to carry out its essential role in Uganda,” she said.

His organisation, Chapter Four Uganda, said he had been denied access to legal representatives and that his family had been barred from seeing him.

Kenneth Roth, the executive director of Human Rights Watch, said Mr Opiyo was being punished for exposing the ills of the government.

“He pulled no punches in challenging President Museveni's oppressive government and regularly described abuses to the media,” he said.

The World Movement, a network of civil society groups, said it was “extremely alarmed by Uganda's abduction of Nicholas Opiyo.”

“We add our voices to the many others around the world calling for him to be released immediately.”