On Saturday, PC Blades and PC Clough died when a Volkswagen Passat, which was going the wrong way on the A66 at South Bank, hit their vehicle.
The five young men in the Volkswagen also died and inquests into all seven deaths opened on Thursday.
Police said 17 people, aged between 16 and 61, had been arrested across Teesside as part of an investigation into the lead-up to the crash.
They have been held on a range of offences including possession of a firearm and being part of an organised crime group.
On Wednesday, Natalie McDonald, 34, died along with her seven-year-old niece Valentina Foster in the fire in Grangetown.
Natalie’s mother, Lisa Kirton, described her as “a beautiful soul, who would have done anything for anybody”.
Valentina, who was known as Tina, was staying at the house for the summer holidays and had been “dancing around the living room” only the previous night.