A person close to the woman who triggered the investigation that ended the CIA director David Petraeus' career says the first anonymous email in the case was sent to Gen. John Allen, the top U.S. commander in Afghanistan.

The person says the mysterious email in May came from someone who used the handle "kelleypatrol." Allen forwarded it to Tampa socialite Jill Kelley. The person close to Kelley spoke on condition of anonymity because the investigation is ongoing.

That email, which investigators traced to Paula Broadwell, the CIA director's mistress, warned Allen to stay away from Kelley. In the email she said she knew Kelley and Allen had a meeting scheduled.

Kelley received as many as five anonymous emails in June, and one noted an upcoming meeting with Petraeus.