Authorities believe a 14-year-old girl is in grave danger and may have been abducted after her father's body was discovered, shot and dumped in a ditch in the Houston area.

The FBI has joined the investigation into the disappearance of Adriana Coronado of Katy.

An Amber Alert issued by the Walker County Sheriff's office Monday suggests the teenager has been abducted.

Sheriff Clint McRae says Adriana could be in grave danger. She was last seen Saturday in Katy, 30 miles west of Houston.

Authorities say the body of her father, Caesar Vladimir Coronado, was discovered Sunday in Walker County, about 80 miles north of Houston. He had been shot to death and his burned pickup truck was found near Conroe, 45 miles south of where his body was found.