SHANGHAI, May 25 -- TAIWAN prosecutors have taken Chao Chien-min, Taiwan leader Chen Shui-bian's son-in-law, into custody for supposedly taking part in insider stock trading.

Prosecutors questioned the Chao family yesterday, including Chao's father, mother, brother and sister-in-law, Taiwan media reports said today.

After an 11-hour questioning yesterday, prosecutors decided to keep Chao in custody at midnight, to prevent him from leaving the area and from contacting or possibly coercing the other suspects.

The other four suspects were allowed to go home.

Chao was moved to Taipei's detention facility at about 6:45am today.

A spokesperson for Taiwan's prosecutors said that Chao is under great suspicion, though he has denied his involvement in the scandal.

While undergoing the questioning, all of the family members passed the blame to Chao's father, Chao Yu-chu, Taiwan media reported. But prosecutors were skeptical of their allegation.

Chao Chien-min, a doctor, was accused of using his mother's name to buy shares in the ailing Taiwan Development and Trust Corp just before their value skyrocketed. Chao profited greatly, earlier reports said.

Taiwan Development and Trust Corp had financial problems and difficulty getting loan approvals.

Following a dinner between Chao and executives of Taiwan Development and heavyweight stock speculators, Chao bought shares in the company. The share price skyrocketed after a banking consortium bailed it out.

The mounting criticism of Chen's family forced Chao to apologize publicly and to resign from Chen Shui-bian's Democratic Progressive Party. Chao offered to donate some of the profits from the deal to charity.

Chen also apologized to the Taiwanese public on Saturday for the recent scandals, including his son-in-law's, that have caused his popularity to plunge.

Chen's wife Wu Shu-chen had been accused of profiting from insider trading in another case and from accepting department store vouchers.

By Zhang Liuhao