Lay Vannak, the recently ousted governor of Takeo, was arrested on Sunday afternoon in connection with the suspicious death of a 36-year-old National Assembly staffer, according to Ministry of Interior spokesman Khieu Sopheak.

Vannak’s arrest is the culmination of days of speculation about the death of Chev Sovathana, who was found hanged in her room in Takeo in January. Police initially ruled her death a suicide, but reopened the case as a murder investigation after family members raised suspicions.

Sopheak on Saturday described the case as “a knot” that police investigators are working to undo. “We are reinvestigating this case because of the dissatisfaction of the family and our authorities, who were also dissatisfied,” he said.

Vannak’s brother, provincial Deputy Police Chief Lay Narith, was taken into custody on Saturday in connection with the death, along with four other suspects – Chan Ry, Sovathana’s maid; Choem Vuth, Ry’s husband; Men Sakmay, Vannak’s driver; and Tak Ratana, Narith’s driver.

National Police spokesman Kirth Chantharith confirmed that the court questioned the five on Sunday.

In a statement posted to Facebook the day before his arrest, Vannak admitted to a yearlong affair with Sovathana but denied involvement in her death. Instead, he insisted that Sovathana, who was a CPP Youth working group member, had killed herself after he tried to break off the relationship when his wife found out.

“I would like to strongly deny all the accusations that my brother and I killed sister Chev Sovathana,” Vannak wrote. “My brother and I made no evil decision to kill her . . . I believe the judicial system and our courts will provide justice for me and my older brother.”

The former governor, who is a member of the ruling Cambodian People’s Party’s Central Committee, added that he was “not running away from the CPP party or my country”.

In a follow-up statement posted on Sunday, Vannak claimed that Sovathana had attempted suicide multiple times before.

He was arrested hours later, shortly after he attended the appointment ceremony of the new governor of Takeo.

Officials have refused to say whether Vannak’s sudden transfer last week from the governorship of Takeo to an unspecified position at the Ministry of Interior was related to the murder investigation.

In a two-hour speech to teachers on Koh Pich on Sunday, Prime Minister Hun Sen said the recent removal of two provincial governors in less than three months – apparently a reference to Vannak and former Kampot Governor Chan Chesda – was hurting the ruling party, according to a teacher in attendance.

“[Hun Sen] revealed that one person who was assigned to be provincial governor had an affair . . . and did not keep it a secret affair,” said the teacher, who spoke on the condition of anonymity because it was a closed-door meeting.

“And he sent a message to all working groups not take an example from him.”

Phnom Penh Municipal Court spokesman Ly Sophanna confirmed that Prosecutor Sieng Sok issued a summons for Vannak on Sunday. The summons “allows the judicial police officer to call for police forces to compel such person to appear before” the judge, Sophanna said in a message.

Contact details for Sovathana’s family members could not be obtained by press time.

National Assembly spokesperson Leng Peng Long confirmed that Sovathana had been employed at the assembly and had been an active ruling party youth group member.

“She was a hardworking person,” he said. “We regret her loss.”

Additional reporting by Daphne Chen