TRIPOLI, Libya -- One of Moammar Gadhafi's sons, al-Saadi, was extradited on Thursday to Libya from Niger, where he had taken refuge as his father's regime crumbled in 2011, bringing cheers from Libyans as the government prepares to prosecute him for his alleged role in trying to suppress the uprising against Gadhafi's rule.

Al-Saadi becomes the second son of the ousted and slain leader to be held in custody in Libya. His brother Seif al-Islam was captured in 2011 and has been held in a western mountain prison by a militia that is putting him on trial, refusing to hand him over to the central government for trial.

At the time of the revolt that brought down his father, al-Saadi headed a brigade of special forces that was involved in the crackdown against protesters and rebels. But he is perhaps even more notorious among Libyans for his dark career in soccer, the country's most popular sport.

A playboy with a lavish lifestyle, al-Saadi treated the country's soccer league as his personal fiefdom. He played for several Libyan teams -- and for an Italian team until he failed a drug test. At various times, he headed Libya's soccer federation and its national team.

In one case, security forces opened fire on fans in a 1996 match attended by al-Saadi, killing a number of people in murky circumstances. He is also suspected in the 2005 killing of Bashir al-Riyani, a popular Libyan soccer player who was a vocal critic of Gadhafi's regime. Libyans say that rules were set that the only player's name that could be announced was al-Saadi's -- while others were identified only by numbers.

Cars honked horns in celebration in the streets of the capital, Tripoli, when his extradition was announced early hours in the morning. In the evening, fireworks went off as people cheered and waved flags in the street, according to footage on Libya's Al-Ahrar TV. A group of soccer players held public memorial for al-Riyani.

"This is a joy for all Libyans," one Tripoli resident, al-Sharif Gheith told The Associated Press, saying Gadhafi's family and his regime officials are to blame for the country's woes. "But now, thank God, they are captured and all of the country will be calm," he said.

That seems far from likely, however, as Libya's chaos has spiraled out of control in the three years since Gadhafi's fall. There was skepticism as well, however, with some saying the government was playing up the extradition to divert attention to its inability to bring stability.

Armed militias run rampant, the central state has little authority, and the parliament and prime minister are locked in a power struggle that has burst repeatedly into violence. Last week, armed rioters stormed parliament, killing a guard and wounding six lawmakers and forcing the legislature to move its sessions into a hotel.

"I think the government is ... trying to cover up its failure," said Sulieman al-Azabi, a lawyer and political analyst. "The role of al-Saadi and other ex-regime officials in the events now is very minor."

In the neighbouring nation of Niger, government spokesman Marou Amadou confirmed that al-Saadi had been extradited to Libya. He said that the son of the ex-Libyan leader, as well as his colleagues who accompanied him, "had failed to respect the conditions of his stay in Niger." He said during a Thursday press conference that one of al-Saadi's friends, Abdallah Mansour, had run away, and travelled back to southern Libya where he tried to destabilize the country's government.

"This puts us in a difficult position because Niger is Libya's neighbour, and we have told the authorities in Libya that we will not become a source of preoccupation for them," said Amadou, who is also the country's minister of justice.

He also said that Niger had sought to find a host country for al-Saadi, but there were no takers. "We took this decision in the interest of our country and in the interest of our people, both for today and for tomorrow," he said. He added that earlier, Niger had worried that al-Saadi might be killed if he was handed over to Libya, but no longer feared for his safety and felt that he would be treated humanely in his homeland.

Al-Saadi was smuggled across the desert which separates Libya from Niger in 2011, just as his father's regime was crumbling. He arrived in a convoy of Libyan vehicles, accompanied by several high ranking officials in his father's military. He and his companions were placed under surveillance in a guarded villa. Libya has long argued that he should be returned to face justice.

A Libyan official, who spoke on condition of anonymity in line with regulations, said the 40-year-old al-Saadi arrived from Niger in the early hours on Thursday at the Tripoli airport and was transferred to Tripoli's al-Hadaba prison, where most jailed ex-regime officials are being held pending trial, mostly in connection to the crackdown on the eight-month uprising that toppled Gadhafi's rule.

Photos showed al-Saadi kneeling in a blue prison uniform as Libyan guards shaved his head and beard. The photos were posted on the official Facebook page of the Libya Revolution Operation Room, the militia grouping that is in charge of security in the capital.

Al-Sadik al-Sour, the head investigator for Libya's prosecutor general office, told AP that the extradition was carried out in accordance to a "judicial co-operation treaty" with Niger.

"Al-Saadi is wanted and he will be tried in accordance to the human rights standards," he said, though he could not specify when a trial might begin.

Prosecutor-general Abdel-Qadir Radwan said al-Saadi faces charges in connection to abductions and rapes during the 2011 uprising, misuse of his post and the killing of al-Riyani, according to the state news agency LANA. He said that during the revolt, al-Saadi commanded a security unit that carried out random killings as well as helped bring in mercenaries and funded other armed groups to fight rebels.

Speaking to Al-Arabiya television, Culture Minister al-Habib al-Ameen denied reports that Libya paid billions of dollars to Niger to hand over al-Saadi. Al-Saadi fled to the West African nation as his father's rule fell, and was put under house arrest there, though Niger had until now refused to extradite him, saying he could be killed in his home country.

"Libya didn't pay billions," al-Ameen said, underlining there was "no deal" with Niger. "These reports are spread by those who want to seed sedition and spoil the joy of the Libyan people."

The elder Gadhafi ruled Libya with an eccentric brutality for nearly 42 years before he was ousted by an uprising in August 2011, then captured and killed two months later. He had eight children, most of whom played significant roles in his regime. His son Muatassim was killed along with him when they were captured, and two other sons, Seif al-Arab and Khamis, were killed earlier in the civil war.

The rest of the children still at large sought asylum in neighbouring Algeria, along with Gadhafi's wife and al-Saadi's mother, Safiya. The mother, a sister and two brothers, were granted asylum in Oman in 2012 and moved there from Algeria.

Seif al-Islam, who was being groomed by his father to succeed him in power, was captured during the regime's fall. He is wanted by the International Criminal Court on charges of murder and persecution of civilians during the early days of the Libyan uprising. Its judges have said Libya -- where the court system is still in turmoil -- cannot give him a fair trial, asking Libyan authorities to hand him over.

The government refused -- but it also cannot get a hold of Seif al-Islam to put him on trial. The powerful militia of the western mountain region Zintan refused to give him to the central government, insisting on conducting its own tribunal against him -- yet another sign of the power of militias in the country.