I suspect it was assassination through opportunity. They saw what was going on and saw it as an opportunity to take out Trump without their hand in the murder. It is like the killing of Christ where Pontius Pilate washed hands of any fault and be accused of any blame.
The better analogy was how King David engineered one of his army officers death by giving him ( Uriah ) a dangerous mission without proper support. He killed him just the same.
More than opportunity since they never had a morning meeting with the locals.