NAIROBI — On the evening of March 27, when the pandemic was new and full of terrifying unknowns, Francis Otieno switched on the news. What he saw is now seared into his mind.

Live video showed police officers beating women who were waiting for a ferry ahead of the first night of a nationwide curfew — imposed out of concern for public health — that hasn’t been lifted since. Otieno has spent all of his 23 years in Nairobi’s ghettos and said he understood the message behind the officers’ blows: We will not hesitate to kill you if you don’t comply.

The night after that, 20 minutes past the 7 p.m. curfew, police caught his 18-year-old brother, Ibrahim Onyango, he said, and beat his face into an unrecognizable pulp. He crawled home and bled to death by morning.

“I called him earlier that night and said, ‘If they can beat women like that, they will kill you, Ibra,’ ” Otieno recalled recently. “That’s the last thing I ever said to him.”

Onyango isn’t counted among at least 20 people killed by Kenyan police while they enforced curfew and other coronavirus-related rules such as mandatory mask-wearing. The government’s police oversight authority said 20 had been killed. It also documented 73 severe assaults, some sexual in nature.

Onyango’s death was never formally registered because his family sees such little hope in Kenya’s justice system for it to be worth the effort and because of the potential for further retribution. It’s indicative of what human rights groups say is probably a much higher, but hidden, toll.

Others died because of the curfew and accompanying police brutality in indirect ways that also went largely undocumented. Mothers giving birth, for instance, often couldn’t find transport to clinics, because taxi drivers feared police beatings.

A spokesman for the police force, Charles Owino, didn’t deny the pandemic-era police killings but said officers weren’t out to do harm, and “if a policeman did such a thing, it’s a simple thing, make a report.”

Even if making a report could be the first step toward justice for his brother, Otieno was unswayed.

“Every day in these streets, we see criminals walk free, cops and robbers, even cops who are robbers,” he said. “We want justice. But where would we even start to look for it?”

Since the inception of Kenya’s police oversight body in 2011, only eight officers have been convicted of crimes, less than 1 percent of the cases it has pursued. According to Amnesty International, more than 740 Kenyans have been killed by police since 2007, including at least 130 already this year. A national survey in 2018 found that most Kenyans believed the biggest risk to their lives was violence by police.

Most of the pandemic-related killings occurred between late March and May. Only one case has been brought to trial: the killing of Yassin Moyo, a 13-year-old boy who was shot while sitting on his balcony with his mother, allegedly by officer Duncan Ndiema, who was enforcing curfew two days after Onyango died.

Moyo’s age and obvious innocence propelled public outrage, and numerous human rights groups, as well as the government’s police oversight body, took up the case.

But even with support, the trial has barely moved forward. Because of the pandemic, nearly all court sessions happen online, which has added to an already massive backlog of cases. Ndiema is free after paying a bail of around $9,000 — a huge amount for a poorly paid constable — that his lawyer said was paid in part by colleagues and others.

Like Otieno, Yassin’s father, Hussein Moyo Molte, came up in Nairobi’s vast expanse of slums, home to more than 2.5 million people, and said he knows how the system is stacked against people like him.

“The longer this case takes, the less chance of justice,” he said. “We have 10 witnesses, but with enough time, they will be killed, they will disappear, they will go quiet. That’s how it works: Slow it down until the case falls apart.”

Ndiema’s lawyer, Danstan Omari, said he thought the trial would start in 2022 at the earliest.

“Cases from five years ago have not even been given a date. In that time, judges can also be transferred or retire and delay further,” he said in a phone interview.

And even then, Omari said, his defense strategy on Ndiema’s behalf is one that is sure to be hugely time-consuming and puts the ability to stall or control the outcome of the case more firmly in the police force’s hands.

“Our position is that the bullet that shot the child is a bullet that came from a different police station. We want an inventory of guns from that police station,” he said. “We have demanded the ballistic report, but we have not received it yet.”

The lack of closure will prolong Yassin’s family’s pain, which lives right below the surface of an otherwise happy family.

On a recent day at home, Molte sat in his living room, the walls of which Yassin, an outgoing kid who loved to dress up and strut about, had half-finished decorating with stickers, stars and butterflies. He jovially talked about his and his wife’s business selling shaved ice and little cakes, and played with his son Mukhtar, who is just 2, the youngest of their remaining six children. But at the first mention of Yassin, tears sprang to his eyes.

“Our youngest children still don’t understand,” he said. “They ask me, ‘Daddy, when is Yassin coming home from the hospital?’ ”

Their three-story house is haunted by Yassin’s absence — the bunk bed that isn’t shared anymore, the end of the family’s nightly chats on the balcony where he was shot, the older sister who shared his birthday week and never wants to celebrate again.

That Yassin’s case is the best — or only — chance at justice for any of the families of those killed during the enforcement of coronavirus restrictions has reinforced a disillusionment among activists working toward police reform. Many said it bore the hallmarks of other cases that were eventually thrown out.

“What we have is a system that allows the police to investigate themselves,” said Peter Kiama, the director of the Independent Medico-Legal Unit, a collective of doctors and lawyers who support human rights causes. “So the police will execute an individual either in custody or during arrest, and they are the ones to pick up the body, take it to the morgue and then call the medical experts to examine the body after they have already compromised the scene.”

In 2017, Kenya passed a law that should have created an independent forensic unit, but Kiama said it was never implemented, and his organization is the only one in the country that provides that service.

Other activists offered long lists of other challenges. No witness protection. No funding for human rights work. No safety for human rights activists who are routinely harassed. No sense of solidarity with the poor from more well-off Kenyans. No political will to reform a police force hollowed out by poor training, poor leadership and poor salaries.

“If you’ve worked a dozen cases and nothing has happened, you get discouraged,” said Gacheke Gachihi, who co-founded the Mathare Social Justice Center, a community outreach organization in one of Nairobi’s biggest slums. Instead of convictions, he said, usually the best outcome is still an unjust one: The officer gets transferred to another post.

“If you transfer them, you transfer impunity,” Kiama said. “What we do in this country is transfer impunity from one place to another, and we postpone dealing with the problem. We are living in denial that we have institutionalized police violence.”

With little recourse, both Otieno and Molte voiced desperation. Otieno, unable to hold back his tears, said his decision to let justice for his brother slip away made him feel “like this life was useless.”

Molte dreamed of taking matters into his own hands.

“But even if I met Duncan Ndiema and killed him myself, it wouldn’t bring Yassin back,” he said, his face again wet with tears.

Correction: The story has been modified to clarify the gender of Gagheke Gachihi.