A family dispute has led to the arrest of the father of a murdered St. Louis county girl. Police say Ernie Williamson, the father of Cassandra Williamson, wasarrested this weekend at the home of his estranged wife’s parents, is accused of assault, and will be charged with trespassing and resisting arrest. Williamson’s wife is staying with her parents. Cassandra Williamson was six years old when she was kidnapped from a house where her father was staying last month. Her body was found hourslater. Another man also staying at the house is charged with murder.