An unidentified assailant yesterday stabbed to death the mother and twin daughters of dissident magazine executive Lin Yi-Hsiung, who is awaiting trial on sedition charges, police said.

Lin, a member of the Taiwan provincial assembly, is one of eight executives of the political magazine Formosa who face court-martial charges that they participated in an antigovernment riot in the southern industrial city of Kaohsiung last December.

Police said the assailant entered the house while Lin's wife was visiting him in jail, killed the executive's mother and seven-year-old daughter and wounded his elder daughter, who was rushed to a hospital for treatment of six knife wounds. She was reported in stable condition.

After the attack, Lin, 39, was freed without bail for humanitarian reasons.

Police gave no details or possible motives for the slayings. But police sources said special protection was extended to all of the defendants' families.

Officials refused to discuss the effect of the slayings on Taiwan's politics, but one official told United Press International, "It's obviously a move made either by agents of the Chinese Communists or members of the opposition to stir up more trouble between the Kuomintang [Nationalist Party] and the opposition groups."