A court ordered the release of Kou Wenjie, the leader of Taiwan's second-largest opposition party, after he was arrested on the weekend for alleged graft.

Mr Kou, who ran for president in January, is under investigation for his role in a shopping center redevelopment project when he was Taipei city mayor.

CNN's Victoria Zhen reports.

Taiwan media have been running marathon coverage of the corruption investigation of Kou Wenjie since last week.

The former Taipei mayor and presidential candidate was brought in by prosecutors for questioning last Friday after they raided his house and party offices.

The development culminated with Kou's arrest on Saturday.

He was detained after he tried to leave prosecutors' office during the investigation after refusing to be questioned at night.

The case took another dramatic turn on early Monday morning.

After a late-night hearing at the Taipei District Court, a judge ruled that the evidence provided by the prosecutors was insufficient to justify further detention of Kou and ordered his release without bail.

Over the weekend, Kou's supporters held rallies outside the prosecutor's office in Taipei, calling the investigation a form of judicial oppression and politically motivated.

Following his release, Kou accused prosecutors of making up stories and described their handling of his questioning as extremely oppressive and abusive.

Kou and others were named in May in a scandal in which the developer of the downtown Core Pacific shopping center was given permission to massively expand the floor space available for lease during Kou's term as mayor between 2014 and 2022.