The suspect is described only as a Hispanic male, 25-40 years old, about 5-foot-5 or 5-foot-6, and 160-180 pounds.
On April 13, at about 6 p.m., police say, the suspect approached the 12-year-old with a knife as she was walking near 7900 West Avalon Drive in Phoenix.
He threatened the girl, but she was able to get away. His motives are unclear.
The M.O. sounds similar to the South Phoenix rapist, arrested earlier this month for the sexual assaults of three young girls as they walked to school.
Dejuan Donaldson allegedly would threaten the girls at knife-point before dragging them into abandoned houses and assaulting them.
The description of the suspect in this case, however, doesn't match Donaldson's.
Silent Witness is offering up to $1,000 for information leading to the arrest of the man who threatened the girl. Anyone with information is asked to call 480-948-6377.