Three officers injured when two cruisers collide in Downtown Crossing

Hit looks like it took place between the driver side rear of the cruiser on the truck and driver side front of the one in back. So either they were following one another around a corner at high speed (i.e., responding to a call) or they crossed paths at an intersection and one of them fucked up. Airbags on both vehicles are deployed and the cruiser on the truck seems to have had its rear wheel knocked way out of alignment (or cracked a control arm/spindle) from the bottom out, but rear class is intact, which suggests a sudden hit at moderate speed. If they were following, the lead car took a sudden turn and deceleration that the follower didn't anticipate, resulting in the collision at speed. In the intersection scenario, one or the other either ran a red/stop or was screaming down the street not paying attention for some other reason (self-importance, texting, yawning, responding to a call, drag racing...).

My guess is that the rear one hit the front one, which spun and came to a stop instead of hitting something else.

The “officer needs assistance” was more likely an “OT call” meaning an officer was screaming into the radio for help. Someone might have been assaulting him or was witnessing something that immediately required more units. Cops do get hurt you know, as we learned with the sad Yarmouth incident just a few days ago.

Or if you care so much, go to BPD Headquarters and pay the money for the report and stop asking people on the internet to do it for you.

Whose insurance will go up as a result of being at fault in this accident? The city's.