ISTANBUL (Reuters) - The head of Turkey's military-run business conglomerate was jailed on Thursday pending trial over the 1997 toppling of the country's first Islamist led government, raising a symbolic challenge to the military's economic power.
The Ankara court order to jail retired lieutenant-general Yildirim Turker along with eight other serving and retired officers, brought the number held pending trial to 35 since prosecutors launched an investigation earlier this month.
Turker, according to media reports, had been head of personnel in the General Staff and belonged to a group within the top brass, known as the Western Study Group, suspected of being behind moves to make prime minister Necmettin Erbakan quit 15 years ago.
The episode is often referred to as Turkey's "post-modern coup" as the generals used pressure behind the scenes rather than overt military force employed in three earlier coups.
According to the pro-government Sabah newspaper, Turker is likely to be questioned over alleged psychological operations to undermine Erbakan, using a television series to sow mistrust of a government that the military viewed as a threat to the republic's secular order.
Turkey's current prime minister, Tayyip Erdogan, had belonged to Erbakan's party. Since coming to power with a new party a decade ago Erdogan has made it his mission to curb the political power of the military, the second largest in NATO.
While his government passed reforms to cut the military's influence, state prosecutors launched a series of judicial investigations into army takeovers dating as far back as 1980 and more recent alleged conspiracies against Erdogan's government.
Despite the military's loss of influence, it retains considerable economic clout through the Oyak Group, a privately-owned pension fund and holding company whose interests range from steel to cement and automotive sectors.
Just two weeks before his arrest, Turker visited Erdogan in Istanbul to donate an electric car, produced by Oyak's joint-venture with Renault, to the prime minister's office.
While the investigation into Turker does not concern his time at Oyak, his detention could raise questions about whether the military is vulnerable to a challenge over its control of Oyak and other economic assets.
Earlier this week another court accepted an indictment against ten employees of an Oyak security firm over allegations that security camera footage at the building where a judge was shot dead in 2006 had been deliberately wiped.
"I don't think there is any question that this is a politically and ideologically-driven judicial investigation," Istanbul-based security analyst Gareth Jenkins.
"We are seeing a number of things which are a cause concern. One is why we've suddenly got several cases against OYAK all being conducted at the same time."
The court also sent to jail retired general Fevzi Turkeri, former head of the gendarmerie paramilitary force, whose house was searched on Wednesday before his detention.
Turker and Turkeri were both sent to Sincan prison in Ankara. The other seven, all serving army officers, were sent to Mamak military prison.
They had been hauled in for questioning after the Ankara chief prosecutor issued arrest warrants on Wednesday for around a dozen serving and retired officers.
The Turkish armed forces staged three coups between 1960-1980 and the perpetrators of the last of those takeovers were put on trial in Ankara court earlier this month.
Erbakan, who died of heart failure aged 85 in March last year, pioneered Islamist politics in Muslim but strictly secular Turkey and paved the way for the later success of Erdogan's AKP.
In the first wave of detentions on April 12, police arrested 31 people including top retired General Cevik Bir, who was one of 18 people subsequently sent to jail pending trial to prevent the risk of them fleeing.
Last weekend, eight more people, including a retired major general, were remanded in custody. There is no provision for bail in Turkey and pre-trial detention can drag on for months.
The leader of the main opposition CHP party, Kemal Kilicaroglu, has said the investigation was turning into a "witch hunt".
Erdogan has warned against such a development but said support for the military intervention that came from business leaders, the media and academics should be revealed.
Hundreds of military officers, including top serving and retired commanders, are now facing trials, accused of involvement in the alleged "Ergenekon" and "Sledgehammer" coup conspiracies against Erdogan and his AK Party government.
Writing by Daren Butler and Simon Cameron-Moore; editing by Ralph Boulton