The Anti-Gang Unit (AGU) arrested three suspects in connection with the Christmas Eve shooting of two children in Valhalla Park.
The shootout left two children, aged four and six, dead and five others injured.
Twelve people were on Thursday morning taken in for questioning.
AGU Commander Major-General Andre Lincoln said one suspect was arrested in Athlone while the other two were arrested in Kriefgat.
“With the arrest, we seized a whole lot of medical supplies, R29 000 in cash, cellphones and a gas welding regulator. We’ve also taken in six people for questioning, then at Kriefgat, took a further six for questioning.”