It has been more than two decades since the assassination of one of the most prominent business figures in Turkey and a prime suspect in the murder is still at large.

Today marks the 23rd anniversary of the assassination of tycoon Özdemir Sabancı of Sabancı Holding, one of the leading business conglomerates in Turkey.

Revolutionary People's Liberation Party-Front (DHKP-C) terrorist Fehriye Erdal and two of her associates murdered Sabancı, senior executive Haluk Görgün and his secretary Nilgün Hasefe in a brazen attack on January 9, 1996, at the Sabancı Center, the holding's main headquarters in Istanbul.

Erdal's two associates, Mustafa Duyar and Ismail Akkol, were apprehended by Turkish security forces. Duyar was killed in a prison riot in 1999 and Akkol is serving a life sentence.

Erdal fled Turkey following the assassination and it was in 1999 when she resurfaced in Belgium's Knokke city with a fake passport after a fire broke out in her apartment.

She was handed a 15-year prison sentence by a Turkish court in a trial heard in absentia.

In 2006, a Bruges criminal court tried Erdal for being a "gang member" and put her under house arrest. She ran away just two days before the court slapped her with four years in prison and 10 years of public rights deprivation. The rulings were later upheld by an appeals court as well.

The Bruges court listed the DHKP-C as a "terror group."

Erdal and other DHKP-C members tried in Belgium were accused of using fake ID cards, possessing weapons and explosive materials, being terror group members, planning acts of terrorism and racketeering.

However, Belgium rejected Ankara's extradition request for Erdal as the death penalty was still in force in Turkey back then. Erdal's request for political asylum was also rejected by Belgium.

In 2007, Belgium's Supreme Court reversed the ruling by the Bruges court to list the DHKP-C as a terrorist group and ordered the release of all DHKP-C terrorists, detained or convicted.

In February 2008, the Antwerp Court of Appeals refused to designate the DHKP-C as a terrorist group.

The court rejected trying Erdal and other DHKP-C terrorists for their crimes committed abroad and only tried them for possession and use of weapons and forging documents.

The Antwerp court sentenced Erdal in absentia to two years in prison and fined her 1,230 euros ($1,400). However, the ruling was reversed following an objection by Belgium Federal Prosecutor's Office.

The Supreme Court later designated the DHKP-C as a "terror group, criminal organization and gang," saying that its members can be tried in Belgium regardless of where they had committed the crimes, authorizing the Brussels Court of Appeals for the trials.

The Brussels Court of Appeals launched a retrial in 2009 and ruled that the DHKP-C did not perform any act of terrorism in the country, saying the suspects and convicts were to be punished for crimes committed individually.

The court registered Erdal as a "gang member" and she was given a two-year prison term in absentia.

On May 25, 2016, 20 years after the Sabancı assassination, a Brussels criminal court ruled that Erdal should be tried in Belgium over crimes she had committed in Turkey.

A Belgian prosecutor sought a 30 years aggravated prison sentence for Erdal and an additional security precaution of 15 years.

The criminal court reached a verdict in February 2017 in absentia, handing Erdal a 15-year sentence for her crimes committed in Turkey.