Murder squad detectives have been granted a further 36 hours to detain and question a suspect over a fatal hit-and-run rampage.
Nine victims remain in hospital, with two of the injured adults in a critical condition and five children also receiving treatment after the driver of a white van brought bloodshed to the streets of Cardiff.
As officers quizzed a 31-year-old man, tributes were paid to Karina Menzies, 32, who died after she was knocked down outside a fire station in the Welsh capital.
And it emerged one of her children, who is disabled, is on a "dream holiday" in Florida and does not know of the tragedy.
More than 70 officers from South Wales Police were working on the investigation, studying CCTV footage and appealing for witnesses to come forward to help build a picture of what happened.
Detective Superintendent Paul Hurley said the suspect carried a weapon and left his Iveco van to physically assault people. The officer said: "We are aware the suspect assaulted people outside his vehicle," and he added police were "looking to identify and recover" the weapon - which was believed to be a crook lock.
There were also unconfirmed reports police were investigating if the driver was involved in a domestic incident before the rampage. A key part of the inquiry is focused on establishing who owns the white van.
Mr Hurley urged witnesses to get in touch and asked for information about a black Renault Clio seen driving on the wrong side of the road of Western Avenue, not far from Cowbridge Road West, where one crash happened. There were no full registration details for the Clio but officers said it carried an 05 plate.
The horrific events began when police received calls about an incident in Crossways Road in Ely at 3.30pm.
This was soon followed by other reports of hit-and-run collisions in several locations in the west of the city, including Grand Avenue, Cowbridge Road West and the Leckwith Retail Park. A total of 14 people were injured in the crashes.