A close aide to Gen Chavalit Yongchaiyudh yesterday dismissed reports that the former prime minister was involved in planning the bomb blast at the Central Festival Samui mall in Surat Thani on April 10.
Lt Gen Pirat Sawamiwat issued the denial after reports that Gen Chavalit was implicated in the car bomb attack on Koh Samui went viral on social media.
Gen Chavalit was accused of meeting insurgents in the South while attending the Khao Chong Chang memorial ceremony in Surat Thani earlier this month.
The former premier only laid a wreath and gave a speech to former communist defectors at the ceremony, Lt Gen Pirat said.
The allegation against Gen Chavalit followed statements by the authorities that the blast was politically motivated and that politicians were involved.
Prime Minister Prayut Chan-o-cha, who was also asked about the reports, said he knew as much as everybody else.
Gen Prayut told the media not to report that he had anything to do with the allegation against Gen Chavalit.
However, the premier reiterated that former politicians could be behind the blast, which in his view was intended to stir up political conflict.
Authorities cannot identify who it could be right now, he said. He also said the blast could be the result of a business conflict between influential groups but ruled out a connection to the southern insurgency.
Deputy Defence Minister and army chief Udomdej Sitabutr said that the authorities have been examining whether political figures in the South are implicated in the explosion.
Gen Udomdej also insisted that the blast was not caused by any groups in the three southernmost provinces seeking to widen their insurgency.
Meanwhile, Nukoon Yongnoo, 59, a manager of a cable television business and a restaurant owner in Phatthalung, appeared at Muang Phatthalung police station to give a statement yesterday.
Mr Nukoon said he decided to go to the police station after he noticed one of two police identikit images circulated by the media bore a resemblance to him.
He said he was at his restaurant in tambon Lam Pam, Phatthalung, when the bomb on Samui went off.
Pol Col Phawat Prachansit, head of Muang Phatthalung police, said no arrest warrant has been issued for Mr Nukoon.
At the moment there is nothing to implicate Mr Nukoon, according to police.
Meanwhile, authorities are looking for three vehicles: a Mitsubishi Triton pickup truck, an Isuzu D-Max pickup truck and a Honda Civic which the bombers are believed to have used as their escape vehicle after the bombing.
Police said that the colours of the vehicles and some of the car parts might have been changed to alter their appearance.
Police said the three vehicles are believed to be in the southernmost provinces, saying their discovery could lead to the arrest of all the suspects.
Abdulroning Dueramae, or "Bangyi", a second-hand car dealer, who was detained by the military in Pattani, allegedly told authorities that the Isuzu D-Max pickup truck was purchased by a man named "Baelee".
However, Mr Baelee had disappeared after Mr Abdulroning was arrested.
Meanwhile, National Council for Peace and Order spokesman Col Winthai Suwaree said Narin Umnongbua, alias "M Suadaeng", was released without charge due to a lack of evidence linking him to the explosion.
Mr Narin was detained by the military on April 11 in Nonthaburi under Section 44 of the interim constitution.