"There was a time when I thought she was going to hurt the kids," Barretto says, referring to Spears' two young sons, Sean Preston, 2, and Jayden James, 1.

Barretto says at one point he and another member of the singer's security team became concerned that Spears was "shutting down."

"He said she'd been talking about suicide then, and this was the same. Britney was sobbing. She screamed," says Barretto. "[He said] 'I'm worried about the kids. Don't let her go swimming with them.' I asked, 'Is she going to drown them?' He said, 'I don't know.' I started to cry. How am I supposed to protect someone like that?"