Britney Spears is to be investigated by social service officials concerned about the welfare of her children, it has been reported. The Los Angeles Department of Children and Family Services is apparently trying to track down the singer for a meeting. Miss Spears, 25, split from her second husband, Kevin Federline, last month, and since then has been a fixture on the Hollywood party circuit. She has been photographed – minus her underwear – at nightclubs in Los Angeles and Las Vegas, alongside socialites Paris Hilton and Lindsay Lohan. According to newspapers in the U.S., authorities fear she is failing...