Basika Mukti, Lesotho Police Commissioner, said in a written statement that Taban ordered the beating of Labello Taban to allow his current wife, Messaya, to become the first lady.
Gunmen shot dead Labello Taban near her home in the capital, Maseru, in June 2017.
She was negotiating a divorce from Taban before she died.
The documents stated in the statement that the prime minister and his wife met the alleged leader of a gang and promised them $ 177,000 and jobs to kill Lepolio before he was installed as prime minister, the police said in a written statement.
Police said Thaban also shared the address of his ex-wife’s home with her murderers and began observing the Leopolio movement.
They tried to kill Liblilo on June 12 but they failed and reported the incident to the police, according to Maketi.
Then they knocked on the road and killed them to Labello two days later on their way from a meeting with an unnamed broker, who is now a state witness.
The mediator was negotiating a truce between the two women in Vicksburg, a small town in neighboring South Africa, according to the affidavit.
Thaban married his current wife Maesaiah, two months after Lipolelo was killed.
Maesaiah was accused of killing Lipolelo and attempting to kill another woman, who was with the former first lady when she was killed.
The former prime minister has not been charged, despite police attempts to prosecute him. His lawyers have argued that he has immunity because of his position.
Thaban stepped down in May after months of pressure from his party to resign over his alleged involvement in the case.
Mokete said he would be charged with murder now while he was no longer in power.
Police re-arrested Maesaiah last week and her previous bail was revoked for technical reasons.
The court ordered a new bail application and said that a different judge must hear the case.