The step-son of Malawi's ex-President Peter Mutharika has been acquitted of all charges in a case in which he was accused of human trafficking and aggravated manslaughter.

Tadikira Mafubza and seven other men were arrested in November 2022 after police said they were linked with the deaths of 29 suspected Ethiopian immigrants whose bodies were found in an unmarked mass grave.

Ex-President Mutharika said at the time he was shocked by the police action, saying his step-son was arrested without there being any evidence linking him to any crime.

After an ordeal lasting more than 19 months, Mr Mafubza and his co-accused were cleared following a full trial.

"We are pleased with the outcome," Mr Mafubza's lawyer said on Wednesday.

"To be honest, we saw it coming as the evidence [against our client] was disjointed."

However, Dzikondianthu Malunda, an official for the Directorate of Public Prosecution, said the ruling had "come as a suprise".

Mr Mafubza himself declined to comment on his aquittal as he left the courtroom on Wednesday, only stopping to pose for photographers' pictures.

In October 2022, police found a grave filled with dozens of bodies in a forest in the northern district of Mzimba after young boys reportedly detected a foul smell.

The corpses were of boys and men believed to be Ethiopian migrants being trafficked to South Africa.

Malawi is a major trafficking route for migrants from Ethiopia and Somalia.

After police launched a search for Mr Mafubza, he handed himself over at their headquarters in the capital, Lilongwe.

The former governing Democratic Progressive Party (DPP) had described his arrest as a political witch-hunt against Mr Mutharika's family and his supporters.