DENVER — An Ethiopian jail guard accused of torturing and killing dozens of people during government-sponsored violence in the 1970s was sentenced Friday to 22 years in prison for immigration crimes by a federal judge who said the U.S. cannot become a refuge for human-rights violators.

Defendant Kefelgn Alemu Worku had lived quietly in the Denver area for eight years until 2011, when another Ethiopian recognized and confronted him outside a cafe with the words, “I think I know you,” before alerting authorities.

Worku was convicted last year of assuming another man’s identity and lying on U.S. immigration forms by denying that he committed acts of political persecution.

“The risk that this country becomes regarded as a safe haven for violators of human rights is such that the maximum sentence is required,” U.S. District Judge John L. Kane said during sentencing, adding there was undeniable evidence that Worku had a role in war crimes. “The relatively harmless lifestyle he has had in the United States does not change the character flaw of psychopathy.”

Two witnesses testified during the hearing that Worku routinely beat them and others at Higher 15, a detention center established during the political violence in Ethiopia known as the Red Terror. Human Rights organizations, including Amnesty International, have said thousands of people were killed in the violence in the African nation.

Abebech Demissie said she was a 16-year-old high school student in 1977 when she was taken to the prison and watched Worku shoot and kill people, including a teenage boy.

He then ordered other prisoners to “clean the blood off the floor with anything we could find, including our tongues,” Demissie said.

More than once, she said, Worku pointed an AK-47 assault rifle at her head then spared her life, making it hard for her to testify against him. But his refusal to accept responsibility – and what she described as his arrogant smirk – reminded her that he was “still a bloodthirsty monster,” she said.

“He must be removed from society for the longest possible time,” she added.

In rambling testimony before he was sentenced, Worku denied the abuse.

“If I was who they are accusing me of being – a monster – I don’t deserve to live,” he said in a scratchy voice, wearing beige prison scrubs and speaking through an interpreter. “I wasn’t that kind of a monster. I didn’t have that kind of authority.”