Troubled superstar Britney Spears is watched closely by her employees at all times because they are worried she will attempt to hurt herself - or even her two kids. The singer's former bodyguard, Tony Barretto, claims he was warned by his predecessor not to let Spears or her young sons Sean Preston, two, and Jayden James, one, out of his sight - especially when the 25-year-old star is in the swimming pool. Barretto says, "(I was warned), 'Don't let her go swimming with them'. "Shocked, 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? "She's unpredictable. No one knows what she'll do next." Barretto's revelations formed part of his testimony during Spears' court battle with ex Kevin Federline over custody of their two children, and could mean the star loses custody of the tots.