Niyazov escaped unhurt after, as he claims, gunmen opened fire on his motorcade on 25 November. The Turkmen president has since launched a fierce police crackdown against the suspected perpetrators. Some human rights watchdogs claim that more than 100 people have been arrested following the alleged assassination attempt.
Turkmenistan's National Assembly, the country's highest legislative body, approved the sentence for Shikhmuradov at a session in the capital, Ashgabat, on 30 December. The decision ignored calls by some Turkmen officials for the death penalty but also overruled a Supreme Court decision of 25-year prison sentences for traitors.
At the session, which was broadcast on state television, Niyazov said: "Let's drop the word 'death.' Life is given and taken by God. So let's impose a lifelong sentence by revoking the Supreme Court decision. Instead of a 25-year [sentence], let's adopt lifetime imprisonment."
Two other exiled former officials, former Central Bank chief Khudaiberdy Orazov and former Ambassador to Turkey Nurmukhammed Khanamov, received the same sentence, in absentia.
Shikhmuradov, a former Turkmen foreign minister and ambassador to China, publicly broke with Niyazov's administration in 2001, declaring himself an opposition leader in exile. He has since been accused of an array of crimes, all of which he was shown confessing to on Turkmen state television on 29 December.
During the confession, Shikhmuradov -- reportedly detained recently -- confessed to masterminding a coup attempt against Niyazov. He said Orazov and Khanamov had helped him plan the coup. "When we lived in Russia, we took drugs and, while in a state of intoxication, prepared people and recruited mercenaries to carry out a terrorist attack. Being part of a criminal conspiracy, we were making promises to those who agreed to carry out our order, which was to destabilize the situation in Turkmenistan, to undermine the constitutional order, and to carry out an assassination attempt against the president of Turkmenistan," Shikhmuradov said.
Human rights groups and analysts have denounced the sentences as unfair and have compared the proceedings to the Stalinist trials of the 1930s that were designed to eliminate the opposition.
Aaron Rhodes is executive director of the Vienna-based International Helsinki Federation for Human Rights. He told RFE/RL, "It's quite clear that many, many people have been arrested there [in Turkmenistan] on an arbitrary basis and that the alleged assassination attempt is a pretext for a wave of repression in Turkmenistan that's quite unprecedented in recent years."
Shikhmuradov said he was making his confession voluntarily, but Elizabeth Andersen, the executive director for Europe and Central Asia at Human Rights Watch, said she is almost positive the confession was dictated to Shikhmuradov.
Accounts of how Shikhmuradov entered Turkmenistan from his unknown place of exile vary. Turkmenistan's prosecutor-general said Shikhmuradov came to Turkmenistan through Uzbekistan on the night of 23 November to carry out the attack of 25 November.
In his 29 December confession, Shikhmuradov said that he entered Turkmenistan in September and had spent the fall preparing for mass protests against Niyazov. He said the protests were set to begin at the end of November.
But in a statement posted on 25 December on the website of Shikhmuradov's People's Democratic Movement of Turkmenistan, he said he had turned himself in to end the mass arrests that followed the alleged attack. He admitted to nothing more than trying to organize mass demonstrations against Niyazov's rule.
Niyazov announced Shikhmuradov's arrest on 26 December.
The methods the Turkmen government has used to investigate the alleged assassination attempt have drawn international attention. In early December, the U.S. State Department accused Turkmenistan of violating international legal procedures in the arrest of a U.S. citizen, Leonid Komarovsky, who was detained in connection with the alleged plot. The State Department also called on Ashgabat to conduct its investigation in a "full, fair, and transparent" manner.
On 9 December, the European Union issued a statement criticizing the detention of numerous relatives of the alleged instigators of the attack. The EU statement demanded that Turkmen authorities act in "full compliance" with the country's international human rights obligations and follow due process of law.
And in a written statement on 31 December, U.S. State Department spokesman Philip Reeker said Turkmen authorities had carried out summary trials, arrested opposition members and civil-society activists apparently unconnected to the attack against Niyazov, and denied U.S. requests for consular access to Komarovsky.
Reeker said Washington is calling on Turkmenistan to respect its commitments to the Organization for Security and Cooperation in Europe (OSCE) by allowing an OSCE team to travel there to investigate alleged abuses. The U.S. representative to the OSCE, Douglas Davidson, has said there were reports that numerous confessions had been extracted by torture.
But Rhodes of the Helsinki Federation said that "regurgitating the old cliches" about how Turkmenistan should abide by its international agreements is not enough. The situation in Turkmenistan, he stressed, is desperate. "There's got to be a stronger form of engagement and pressure put on that government. It has to also involve international corporations and various business arrangements involving the natural resources of Turkmenistan in order to make it work," Rhodes said.
Further, Rhodes pointed out the danger that other Central Asian rulers will "mimic" the behavior of the Turkmen president. "That's the disturbing thing about governments like that of Turkmenistan. And another example is Belarus. The neighbors start getting ideas about how they can keep their populations under control and become increasingly autocratic. And they find that they can do these things and get away with it because the international system is pretty weak," Rhodes said.
Bess Brown is an expert on Central Asia. She told RFE/RL that she doubts that other Central Asian leaders will follow Niyazov's lead. She said Turkmenistan's long-standing isolationism makes it more difficult for the international community to put pressure on Niyazov than on the other Central Asian leaders. "For one thing, they're more dependent on international goodwill than Niyazov is. This is one of the things that makes it difficult to have any influence on what he's doing. He doesn't really consider that he's dependent at all on the goodwill of the outside world. One doesn't really have any levers that have an effect on him, or very few," Brown said.
Brown deplores the declining interest in Central Asia on the part of Western governments, which she says seem to have given up on the idea of trying to improve the human rights situation in the region. "I doubt if it would encourage them to become much more intractable than they already are, because they've already drawn their conclusions from what they've seen happening in the last few months, [that is,] that there just seems to be a declining interest in doing anything much to criticize or demand improvements in all of their human rights records," Brown said.
Brown said Central Asia has lost an opportunity to improve its standing on the world stage following the U.S.-led military campaign against the Taliban in neighboring Afghanistan. They squandered their opportunity, she noted, and said international interest is now shifting to Iraq and the Persian Gulf.
(RFE/RL's Turkmen Service contributed to this report.)