TACOMA, Wash. — A Washington state woman is now facing state charges, as well as federal, in what authorities describe as a child pornography conspiracy revealed by an alert airplane passenger.

Investigators say Gail Lynn Burnworth, of Tacoma, was writing sexually explicit text messages with Michael Kellar as he was on a flight from Seattle to San Jose, California, July 31. Authorities say Kellar was using a large font on his phone, and another passenger became concerned after seeing messages about child molestation.

The passenger alerted authorities. They say Burnworth admitted to having molested a child she lived with and producing explicit videos.

Burnworth and Kellar have been charged federally with conspiring to produce child porn. Pierce County prosecutors also charged her Thursday with child rape, molestation and sexual exploitation.

An attorney for Burnworth did not immediately return an email seeking comment.