Thai officials say a key witness in the shooting deaths of anti-government protesters in 2010, allegedly by soldiers, was detained by the army for her suspected involvement in a recent grenade attack in the capital.

Thai junta spokesman Col. Winthai Suvaree says Nattatida Meewangpla was taken into custody for questioning by soldiers and police before she was handed over to city police. A day earlier, he had denied that the authorities had detained her.

Her lawyer, Winyat Chatmontree, said Nattatida was taken away by a group of men believed to be military officers since last Wednesday.

At least 15 arrest warrants have been issued for suspects for the March 7 grenade explosion at Bangkok's Criminal Court.