In Breaking Bad, season 5, Mike's nine guys' lawyer Dan Waxberg is caught red handed by the DEA while transferring Mike's cash to his nine men's safe deposits. Right after that, we learn from a conversation between Steve Gomez and Hank Schrader, overheard by Walt, that the lawyer ratted on Mike. Mike then receives a call asking him where he is, claiming there to be a "small situation with the money" which needs discussing face to face. He replies that he's at the park with his granddaughter in Palomita, leading the DEA right to him.
Who placed this call ? Was it Waxberg ? Or someone from the DEA ?
The caller begins by saying "It's me, can you talk ?" to what Mike replies "I can" so presumably he recognises the speaker's voice and feels safe telling him where he is. I'm inclined to think it's the lawyer, but I can't confidently recognise his voice.