Lesotho Prime Minister Thomas Thabane was questioned by police on Wednesday over the 2017 murder of his estranged wife, a police chief said.
Thabane was interviewed at his office rather than at a police station, following a request by his party, the All Basotho Convention (ABC).
"We did not see a problem with that (request). It was not imposed on us," deputy police commissioner Paseka Mokete said.
The brutal gunning down of 58-year-old Lipolelo Thabane sent shockwaves through the tiny mountain kingdom, which has a long history of political turmoil.
Two weeks ago, Thabane's new wife, Maesaiah Thabane, 43, failed to turn up for questioning over the same murder.
She has since vanished after a court issued an arrest warrant. Police have no clue of where the first lady is.
"We are still working on other processes to engage... Interpol," police spokesman Mpiti Mopeli told AFP.
The accusations against the 80-year-old prime minister came after investigations revealed that communication records from the day of the murder picked up Thabane's mobile phone number.
The couple had been embroiled in bitter divorce proceedings.
While Thabane was being quizzed, about 600 mainly opposition supporters staged a protest on the streets of the capital Maseru, demanding that he quit immediately.
Carrying placards written "Thabane must go today " and clad in party colours, they chanted "Thabane and his wife must go" and "We want justice for Lipolelo".
Following calls from his own party, Thabane last week said he would leave office on the grounds of old age. He gave no time frame for his departure.