I don't understand what jurisdiction ICE has to enforce traffic laws. We see other vehicles drive around her vehicle, so at most it was a minor inconvenience for ICE. Call the local LE on her if you don't like how she's parked in the road and they can issue a ticket.
Federal agents can arrest people for obstructing them, if you block the road they aren't obliged to defer to local cops and laws, because fucking with federal agents like that violates federal laws. Regardless, none of it justifies a murder.