Sadulloev, the latest such case, disappeared nearly a month ago, prompting a regional media frenzy about his possible murder by a member of the country's first family. Sadulloev heads Orienbank, one of the largest Tajik financial institutions. He reportedly owns at least 13 other large companies in the country.
For Tajiks, however, Sadulloev is best-known as President Emomali Rahmon's brother-in-law, a man who in a short period of time rose from humble village origins to become the owner of a vast business empire. He gathered his wealth, many observers say, thanks to connections. His sister Azizamoh, after all, is the president's wife.
Regional media reports regularly speculate that Sadulloev was killed, or seriously wounded, by one of Rahmon's children, amid the first family's discontent with Sadulloev's growing influence and ambition.
Dodojon Atoullo, an independent Tajik journalist, is a long-standing critic of Rahmon. Atoullo says that the president was disappointed by Sadulloev's "political ambitions."
"Lately, Hasan Sadullaev had started to consider himself an alternative to the president, saying if something happens to the president he would take the job," Atoullo says. "There were two centers of power in Tajikistan: one around Rahmon and another around Sadulloev."
Reaching Too High
Such a story certainly rings a bell in neighboring Kazakhstan. Rakhat Aliev, former son-in-law of President Nursultan Nazarbaev, was a medical doctor before marrying the president's daughter, Darigha.
Aliev eventually rose to head the country's chief tax body before becoming first deputy security minister, a banker, media tycoon, and ambassador. Needless to say, he accumulated an immense fortune along the way. But he did not stop there.
In 2007, when he was charged by a Kazakh court with kidnapping and murder, Aliev claimed he was being punished for having presidential ambitions.
The court, however, found him guilty of kidnapping two bank workers and extorting financial assets from a number of people and companies. In a separate trial by a Kazakh military court, Aliev was also convicted of masterminding a plot to overthrow the government.
Aliev, whose wife divorced him last year, remains out of the country. If he set foot in Kazakhstan, he would face immediate arrest as the courts have sentenced him to a total of 40 years in prison.
Despite divorcing Aliev, Darigha Nazarbaeva also received her own share of "punishment."
She used to accompany her father on important trips abroad. Her party, Asar, was the country's second-largest political bloc. Nazarbaeva was widely seen as her father's successor as president.
However, shortly after the Aliev scandal erupted, Nazarbaeva's party was virtually dissolved and her influence in politics has receded.
Atoullo, the Moscow-based Tajik journalist, says Central Asian presidents do not tolerate anyone, including the closest family members, "who even dream about the presidency."
A Hard Fall From Grace
Indeed, since gaining independence in 1991, Central Asian countries have experienced many changes -- but they have not seen many changes in president. Nazarbaev and Islam Karimov, his Uzbek counterpart, have ruled since the Soviet era, as did former Turkmen leader Saparmurat Niyazov until his death in 2006.
In Kyrgyzstan, former President Askar Akaev stayed in power for nearly 15 years and did not leave until people took to the streets accusing him and his family of corruption and taking over the country's main industries.
Rahmon has ruled Tajikistan since 1992.
All of the presidents have sent their main political opponents into exile or prison. And it seems the punishment for harboring presidential ambitions has been extended to family members, too.
As in Rakhat Aliev's case, those whose presidential ties were somehow severed had to cope with far more than just a broken heart. When Rahmon's daughter Tahmina divorced her first husband, her former father-in-law, Yormuhammad Gulov, was sacked as head of the State Food Company.
But Mansur Maqsudi, an Afghan-American and the former son-in-law of the Uzbek president, lost much more after his marriage to Gulnora Karimova hit the rocks. Soon after marrying into the first family, Maqsudi formed a joint venture with the Coca Cola bottling company in Uzbekistan, becoming the new firm's president.
Although Coca Cola denies receiving any favorable treatment from the government, regional media reports said the joint venture was given access to "the only big bottling plant in Tashkent that met U.S. standards," in the process pushing its chief rival, Pepsi, out of the Uzbek market.
After the couple's divorce, however, Maqsudi's businesses, as well as his Afghan emigre family living in Tashkent, suffered the consequences.
Coca Cola's three plants were raided and their employees harassed. Meanwhile, Uzbek police reportedly rounded up more than 20 of Maqsudi's relatives, driving them to the Afghan border and dropping them off on the other side.
Such stories are starting to weigh on Central Asians, who are growing tired of high-level corruption while ordinary people face rising food prices, unemployment, and poverty.
Alima Sharipova, a university professor in the Kyrgyz city of Osh and an independent expert on social issues, says people in the region are fed up with "presidents giving away their country's wealth to relatives and new relatives as a gift and appointing them to official posts.
"It was presidential family members' greed that brought Askar Akaev's demise," she adds. "And it's not impossible that the same scenario can be repeated in Kyrgyzstan and elsewhere in Central Asia any day."