Two months ago, the department also visited Britney's home, when L.A. Deputy Sheriff Mark Winn questioned her after she illegally drove her SUV with Sean propped on her lap. And this time, “something definitely had happened to Sean,�? says a source.

According to Star Magazine, Britney, 24, and Kevin, 27, had been up late on March 31, in Dallas, where Federline was promoting his new single, “PopoZao.�? But the next day they were back home in Malibu, Calif., when the nanny, who was in another room, took Sean out of his high chair. According to a source, the chair broke as she was lifting Sean and he slipped and fell to the ground.

“As more details surfaced, it became clear that this was a very serious incident. Whether it was a freak mishap or actual negligence remains to be seen.�? Any further investigation will likely be focused on the nanny – not Brit or Kevin, who were not to blame for Sean’s injuries.

Immediately, a scared Spears and Federline took the baby to pediatrician Dr. David Baron’s Malibu office, the source reports. Sean was pronounced fine and sent home. But six days later, on April 7, they noticed the change in his sleeping pattern, and rushed him to see Santa Monica pediatrician Dr. Marna L. Geisler. According to the source, Geisler noticed swelling in Sean’s head and ordered a CAT scan – and the results were “not normal.�? The test revealed the fracture (likely not bigger than a hair-line) and the blood clot.

Meanwhile, TMZ reports when rapper Kevin Federline was asked about his son Sean, in the wake of a surprise call to his home by DCFS... he nodded that Sean was ok.

Spears attorney, Martin Singer issued a statement saying, "DCFS immediately responded and determined there was no problem and no reason to open a formal investigation.

"They determined that the parents weren't involved in the injury and nothing was improper within the home."

Lost Hills Sheriff's Department has also confirmed they accompany department officials while they visit a home as standard procedure