Arizona shooting investigation latest

(AP) _  Arizona authorities say it's not clear what the motive was in an assassination attempt that left six people dead and Congresswoman Gabrielle Giffords in critical condition.  The dead include a federal judge and a nine-year-old girl. In all, 13 people were wounded.

Pima County Sheriff Clarence Dupnik described the suspect as mentally unstable and possibly acting with an accomplice. A quick snapshot of the gunman, 22-year-old Jared Loughner, shows him a somewhat solitary individual. Neighbors recall him as someone who often kept to himself.  They say he wasn't hostile, but didn't warm up to anyone, either.  One former classmate described him as a student who disrupted class with occasional outbursts.

Meanwhile, President Barack Obama is promising a comprehensive investigation into the deadly shootings in Tucson.  The President says authorities don't know what provoked the shooter. But Obama said "we are going to get to the bottom of this.''  The President is sending FBI Director Robert Mueller to oversee the investigation.