Metropolitan police chief Pol Lt-General Sanit Mahathavorn on Tuesday said that engineer Rattakorn Jitsripitaklert, 40, had been released on Bt150,000 bail.

Following the incident, in which a metal structure fell on the workers on Kham Phaeng Phetch 6 Road, arrest warrants were issued for Rattakorn, crane controller Pornchai Buaprathumma, 37, and assistant engineer Boonseub Phankham. The two others have also been released on bail.

Sanit said police would examine documents from contractor Italian-Thai Development PCL and the project owner State Railway of Thailand – to be submitted by next Monday to determine if any executive above the engineering level could be culpable.

Similar previous accidents claimed eight lives.

Don Muang precinct superintendent Pol Colonel Surachet Banthit confirmed that Rattakorn had surrendered but denied the charge of negligence, saying he would only testify in court.