Police have insisted they strictly followed negotiation practices in line with local police standards when attempting to cajole the suspected killer of two university lecturers into surrendering and who later turned the gun on himself.
The police were heavily criticised for their handling of the situation and for not having trained professionals negotiate with the distressed 60-year-old university lecturer, Wanchai Danaitamonut.
Thitirach Nonghanphitak, the Central Investigation Bureau chief, defended the police's decision not to use psychologists in the standoff, saying it was out of concern for their safety and since the suspected killer was well educated and may not have needed them.
Pol Lt Thitirach said the suspect was stressed and probably wanted to speak to someone he trusted, which is why they brought people he knew to speak to him.
"This conformed to negotiation principles," said said Pol Lt Gen Thitirach.
Police officials only supported the negotiations and tried to control the situation. They brought a relative of Mr Wanchai's in to help, he said.
The tense standoff on Thursday ended with Wanchai committing suicide by shooting himself after almost six hours of negotiations during which trusted friends, relatives and police officials pleaded with him to surrender.
Wanchai allegedly gunned down Pichai Chaisongkram, 56, and Natthapol Chumworathayee, 54, in an examination room in front of a graduate student at Phranakhon Rajabhat University in Bangkok on Wednesday morning before fleeing.
He allegedly burst into the examination room and opened fire on the two men with a 9mm calibre pistol.
Lt Gen Thitirach said despite being accused of lacking any tact during the standoff, police were in tune with Wanchai's mental state and tried to allay his fears of ending up in jail by telling him of a previous high-profile murder case that had a more positive outcome for the convicted killer.
They referred to the case of former gynaecologist, Wisut Boonkasemsanti, who was sentenced to death for the premeditated murder of his estranged wife but was eventually released from jail, said Pol Lt Gen Thitirach, adding that Wanchai became noticeably more relaxed upon hearing the details of this case.
"What the lecturer was most concerned about was the possibility of him ending up dying in prison serving a life sentence or facing execution," said Pol Lt Gen Thitirach.
But the police's efforts were in vain, and in a split second Wanchai decided to pull the trigger and kill himself, said Pol Lt Gen Thitirach.
He shot himself at 6.44pm and was immediately rushed by ambulance to a hospital.
The Royal Thai Police regularly organises negotiation training sessions and sends a number of officials to attend more advanced courses overseas to handle such situations, the officer insisted.
Pol Maj Gen Suwat Jaengyodsuk, a deputy chief of the Metropolitan Police Bureau who led police negotiations on Thursday, had completed a negotiation training course in the US, Pol Lt Gen Thitirach said.
The Department of Mental Health expressed its appreciation to the Thai Journalists Association for warning members of the media to be mindful about their live broadcast of Thursday's negotiations either via the television network and Facebook Live.
No such violent acts should be broadcast to audiences because it is a way of spreading fear or relaying scenes of violence that may lead to copycats, said the department.