(CNN) -- After months in hiding, Saif al-Islam Gadhafi was finally tracked down in Libya's southern desert by fighters from the western Zintan mountains.
Once seen as a potential successor to his slain father, Moammar Gadhafi, Saif al-Islam 's capture may mark the end to hopes held by loyalists that the Gadhafi family might seize power again.
As the unrest in Libya began to swell earlier this year, Saif emerged as one of the regime's most visible defenders. He was the first to address the nation about the unrest and detail a plan to address it.
Saif al-Islam later made very public vows to fight to the "last bullet."
His alleged involvement in the bloody crackdown led the International Criminal Court to accuse him of crimes against humanity, including murder and persecution.
It is not yet clear whether he will be brought to trial in Libya, as many military commanders would like, or handed over to the International Criminal Court in the Hague, in the Netherlands.
His support for his father, if not altogether unexpected, surprised some who had previously seen the 39-year-old as the opposite of the elder Gadhafi.
Whereas Moammar Gadhafi years ago launched a program to "destroy imported ideologies, whether they are Eastern or Western," his son speaks fluent English, earned his Ph.D. from the London School of Economics, wrote an op-ed in the New York Times and was a frequent go-between in talks with international officials.
Moammar rarely went anywhere without an ornate Bedouin tent and wearing distinctive tribal dress. The well-traveled Saif, meanwhile, was more likely to appear in Western business attire: a suit and tie.
While the father ran the nation, his son's main job -- at least before his 2009 appointment as general coordinator, a position like many in the nation's government with few guidelines -- was heading a charity, the Gadhafi Foundation.
And lastly, while the elder Gadhafi was known for his heavy-handed rule in Libya and its restrictions on civil rights and more, Saif fashioned himself as a human rights advocate and pushed for democratic and institutional reforms that could give more power and freedoms to the people -- at least before the popular uprising.
Yet for all their differences, Saif's standing in the world was always defined by his father's role.
While some saw the son as more open to change, there was little question -- particularly after the uprising began -- that his loyalty remained first with his father.
At one point during the war, sources close to the elder Gadhafi said that any transition in Libya would have to involve Saif al-Islam, long seen as a possible successor to his father. He denied having any such desire to rule.
Saif al-Islam had been on the run since shortly after the fall of his father's Bab al-Aziziya compound in the capital in August.
His promised fight to the end was finally stopped in its tracks by rebels who had pursued him across the desert.
His hand apparently bandaged from previous clashes but in good health, his final battle may now mean explaining his family's actions before a judge and jury.
Responding to news of his capture, Luis Moreno-Ocampo, the ICC's chief prosecutor, said Saif al-Islam had been a principal actor in the violence seen in Libya after February 13.
"He's arrested, he's alive, and now he will face justice. And that is the most important news."
CNN's Jomana Karadsheh in Tripoli and Laura Smith-Spark in London contributed to this report.