The police - and their boss, minister Fikile Mbalula - have been left red-faced and caught in a PR nightmare now that the arrest of 10 people, touted as a breakthough in the investigation of a Cape Town massacre, has turned out to be a monumental blunder.

Last Friday night police in the Western Cape detained eight men - and later another two - near the Huguenot Tunnel. They made them lie in the road, trussed up with cable ties, and sent out a press release and pictures about their "protracted investigation".

They said multiple units and "intelligence operatives" had "pounced" on a vehicle and arrested suspects whom they suggested were linked to weekend shootings in Marikana, in Cape Town, in which 11 people were killed.

Mbalula arrived at the scene of the arrests to make his own road-side interrogations. He later posted pictures of the men on Twitter and boasted about the "midnight criminal space shake up" to his one million Twitter followers.