I often wonder if Putin is human at all, or a frozen or iron statue. I wonder and can't find confirmation that he is a human being.

- Anna Politkovskaya

Five men were convicted in the shooting death of Anna Politkovskaya outside her Moscow apartment in 2006, but many believe the mastermind got away with murder. The outspoken critic of Russian leader Vladimir Putin was killed on Putin's birthday, spawning speculation that the journalist's assassination was a gift.

Politkovskaya's death should be remembered in light of Republican presidential candidate Donald Trump's continued expressions of adoration for Putin. He gushed over the Russian president Wednesday night in an NBC News forum before an audience of military veterans, which also featured Democratic nominee Hillary Clinton.

"The man has very strong control over a country," Trump said of Putin. "It's a very different system, and I don't happen to like the system, but certainly, in that system, he's been a leader, far more than our president has been a leader."

Trump didn't mention how much easier it is to lead when for all practical purposes you are a dictator.

Politkovskaya's untimely death isn't the only one that seems to have Putin's fingerprints on it. The list also includes Alexander Litvinenko, a former KGB agent who was poisoned in 2006 by two former Russian security officers who slipped radioactive polonium 210 into his tea at a London restaurant. A British investigation concluded that Putin "probably approved" the assassination.

American journalist Paul Khlebnikov, editor of Forbes Russia, who was known for his investigations of corruption in that country, was killed by machine gun fire outside his Moscow office in 2004. And last year, just days after opposition leader Boris Nemtsov told a Russian news website, "I'm afraid Putin will kill me," he was gunned down in Moscow.

Admirers of Putin either don't know or have forgotten how he came to power. The former KGB officer rose to prime minister in 1999 when Russia dropped into an economic abyss under President Boris Yeltsin. Putin's bravado after four Moscow apartment buildings were bombed in a suspected Chechen terrorist attack won him public admiration, though no one was ever arrested.

Putin was elected president in 2000, took control of the news media, and put his friends in charge of Russia's major industries. Unable by law to succeed himself after two four-year terms, Putin orchestrated the 2008 presidential election of Dmitry Medvedev, who promptly appointed Putin prime minister. In 2012 they switched roles again. Under revised law, Putin can serve two six-year terms ending in 2024.

In The New Tsar: The Rise and Reign of Vladimir Putin, Steven Lee Myers tells how Putin in 1989 bluffed an East German mob threatening to storm the KGB compound in Dresden into believing soldiers inside would shoot them. The truth was that Moscow had ignored Putin's call for help. But his ability to lie with a steady gaze convinced the crowd to retreat.

Putin's guile may blind some people to the truth, but presidents must look a dictator in the eye and see him for what he is. That doesn't mean America and Russia can't be friends. But we must choose our friends with great care.