Promises Rehab Facility Served!

Kevin Federline’s defense team was hard at work delivering yet another subpoena ? this time to the Promises rehab facility where ex-wife Britney Spears spent a month being treated earlier this year.

Kevin?s attorney, Mark Vincent Kaplan, confirmed to Access Hollywood an ?administrative executive? at the facility was served with the subpoena on Saturday, as Kevin and his camp continue to build their case in his very public custody battle with Britney over the couple?s two kids.

?They are pursing all relevant evidence from every potential source and every available witness, including witnesses who might actually believe they could succeed in becoming unavailable,? a source told.

source?