In The Nick of Time, Jeanne and Edward Meet

No, it was Alex Duncan. 

The man, who clearly should not be there, had suddenly appeared.

Jeanne looked at him warily and watched as he approached them, step by step, without a care in the world

"Are you curious how I found you so quickly?" Alex snickered.

Jeanne gripped her phone tightly.

"I knew Edward would definitely let you off and might even help you escape. That was why I placed a tracking device on your most trusted assassin, Mason!" Alex looked at Jeanne coldly. "As expected, you almost left!"

Jeanne gritted her teeth and turned to look at Mason.

At that moment, Mason had already started to search for the tracking device on his body.

"Behind you." Alex said, "I let you go on purpose because I knew you would meet up with Jeanne. So, when you weren't paying attention, I had someone stick something on your back. It turns out that in a life and death situation, even an assassin can be careless."