RICHMOND — The arrest of a middle school teacher on suspicion of child sexual abuse this week has raised questions about the West Contra Costa Unified School District's hiring practices, because the teacher was hired while police were investigating him. Ron Guinto, 32, of Vallejo, was arrested about 7:45 a.m. Wednesday in the parking lot of Mira Vista Elementary School. The seventh-grade English and science teacher is expected to be charged with 11 counts of lewd acts on a child under 14 years old, two counts of forced oral copulation and one count of assault with intent to commit sodomy,...