Briefly, he originally lost his citizenship in 1981, for lying about his service as a concentration camp guard on his citizenship application. He was deported to Israel in 1986, tried for, among other things, the crimes of Ivan the Terrible at Treblinka. His misidentification as Ivan, a high profile Nazi, was the basis for Israel’s extradition request. He was tried, convicted, and sentenced to death. In 1993, the Israeli Supreme Court ruled there was insufficient evidence that he was Ivan the Terrible, and that he couldn’t be retried on the other charges as the extradition was based on Ivan’s crimes. He returned to the US in the late 90s, his citizenship was restored, and Justice filed a new complaint based on his non-Ivan crimes, serving as a guard at Sobibor two other camps. He was tried again, his citizenship revoked, and he lost his final appeal in 2004. Obviously the legal machinations are still going on.
He ought to voluntarily agree to go to the Baltic. He'd be safe enough there.