i was not ready for those pictures

The true motive becomes clearer in this article from the PPP - the victim's wife paid the godson to kill her taxi-driver husband because he was cheating on her with another woman. In this version, the alleged murderer did it for a $1000 fee paid by the wife:

Police photo.
The victim, Kao Pha, 48, was a taxi driver with four children from Svay Rieng province. A military police officer who spoke on condition of anonymity, said Kao’s wife, Sao Sam Oeun, 46, had hired their neighbour to kill her husband for having an affair with another woman.

On October 13, her neighbour, Sou Pha, 30, allegedly killed her husband for $1,000 after pretending to need a taxi ride to Siem Reap...
http://www.phnompenhpost.com/national/w ... ers-murder

An artist commissioned by the police or a coroner or postmortem pathologist can probably work from the photo and produce a drawing showing what the poor chap looked like in happier days.

UPDATE: 2022: Sentence Appeal

September 20, 2022
I wanted husband beaten up and not killed, says woman
Buth Reaksmey Kongkea / Khmer Times
A convicted woman yesterday asked the Supreme Court to reduce her life-sentence meted out for allegedly hiring her godson to murder her husband in 2016.

The victim, identified as Kao Pha, 50, from Svay Rieng province was killed on October 11, 2016 but the decomposed body was only discovered in a canal in Phnom Penh’s Por Senchey district three days later.

During yesterday’s appeal hearing, Sao Samoeun, 53, told the court that she had only hired her godson So Pha, 34, to beat her husband up for allegedly living with a mistress and did not tell him to commit murder.
Samoeun said she was angry with the victim and later paid her godson $10,000 to beat up Kao Pah as a warning.

Prosecutor Ngeth Sarath said that Samoeun[wife of the victim], and So Pha [her godson], 34, were sentenced on August 21, 2018 by the Phnom Penh Municipal Court to a life sentence in prison each.
https://www.khmertimeskh.com/501153837/ ... ays-woman/

UPDATE
Woman Appeals Life Sentence for Husband's Murder Before Supreme Court
September 30, 2022

Cambodia News, (Phnom Penh): The Supreme Court on the morning of September 30, 2022 announced the verdict on the appeal of a convicted woman involved in a conspiracy with her godson Sopha, whom she hired to kill her 50-year-old husband because he had a young mistress. The husband was working as a taxi driver in Phnom Penh, while the wife and children were living in Prey Veng province. The crime dates back to October 2016.

As a result of the appeal, the Supreme Court has decided to return the case to the Phnom Penh Municipal Court of Appeal for a retrial, due to some doubts and gaps in information that the Court has not yet considered.

On 11 October, 2022, the husband, Kao Pha, was stabbed to death in his car, handcuffed to a large rock, and dumped in a sewer in Sangkat Choam Chao, Khan Por Senchey, Phnom Penh; the victim's body was later found, on October 14, 2016, tied to a large stone weighing nearly 10 kilograms.

Khim Ponn, Chief Justice of the Supreme Court, said that the convicts were Sao Sam Oeun, 52, (the victim's wife) and Sopha, 34, the godson.

According to the judge, in this case, the Phnom Penh Municipal Court on August 21, 2018 sentenced Sopha to life imprisonment for murder under Article 200 of the Penal Code. Defendant Sao Sam Oeun was also sentenced to life in prison on charges of conspiracy to commit premeditated murder. The Phnom Penh Municipal Court of Appeal maintained the sentences of the defendents, so Sao Sam Oeun continued to appeal to the Supreme Court. Sopha did not appeal.
The two were arrested on October 14, 2016.