Unholy Triangle.

 Now the Feast of Unleavened Bread drew near, which is called the Passover. And the chief priests and the scribes were seeking how to put him to death, for they feared the people.
 Then Satan entered into Judas called Iscariot, who was of the number of the twelve. He went away and conferred with the chief priests and officers how he might betray him to them. And they were glad, and agreed to give him money. So he consented and sought an opportunity to betray him to them in the absence of a crowd. (Luke 22:1-6 ESV)
Both Satan and the angered leaders had failed to trap Jesus on their own - Satan in the Wilderness, and the leaders ever since on an increasing basis.  They were both afraid, and rightfully so.  In Judas they hoped to have the missing key, the insider information to make Jesus fall. Judas knows where to find Jesus - at all times, and when He is most alone, like in the evenings, after leaving the temple (21:38) This unholy triangle is excited about their prospects.