The arrests mark the second time U.S. Immigration and Customs Enforcement officials have targeted suspected war criminals illegally seeking shelter in the United States, the agency said. The investigation, dubbed Operation No Safe Haven II, concluded Thursday.
Of the 50, seven were arrested in Los Angeles, most of them from Central America, according to ICE spokeswoman Jennifer Elzea. Five were arrested in San Francisco.
Among those arrested was a Central American man with multiple criminal convictions in the United States who served as a military officer in his native country. The man served in a unit that committed civilian murders and led to the forcible disappearance of a family, authorities said.
In a statement, ICE said it is "committed to rooting out known or suspected human rights violators who seek a safe haven in the United States."
Those suspected of human rights violations "didn't need to pull the trigger" to be considered criminals, Elzea said.
"Substantial involvement is still a human rights violation," she said.
Ten of the people arrested are also convicted criminals, ICE said. The operation more than doubled the number of suspected human rights violators arrested during the first nationwide No Safe Haven operation in September 2014.
Authorities did not release any further information on the identities of those arrested.
ICE said it has arrested more than 296 people for human-rights-related violations since 2004.
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