BINGHAMTON -- Police say they have no reason to doubt the authenticity of a letter sent to a TV news station forecasting Friday's mass shooting in Binghamton.

Police Chief Joseph Zikuski says they received information earlier Tuesday that the letter, sent to News 10 Now in Syracuse, might not be from gunman Jiverly Wong. He says that information turned out to be incorrect.

Zikulski won't discuss what police think the letter says about Wong's mental stability.

He says he'll leave that assessment to FBI experts.

The rambling letter was mailed the day Wong killed 13 people at an immigrant center. In it he blames his troubles on the police and vows to kill at least two people and himself.