Four letters containing threats and a white powder were found at North Texas schools full of young children on Tuesday afternoon. A fourth letter was delivered to a church in Grand Prairie.

The suspicious letters have been reported at Pierce Early Childhood Development Center, 901 North Britain; and Clifton Early Childhood Center, 3950 Pleasant Run Road; both in Irving.

Both contained threats purporting to be from "al-Qaida."

A third letter was found at the West Garland Head Start Center at 3709 West Walnut, and a fourth arrived at Mesquite Head Start at 650 Lee Street.

Lighthouse Baptist Church, 410 Northeast 27th Street, in Grand Prairie, also received a suspicious mailing.

All the schools were evacuated, and hazardous materials experts were called to handle the suspicious materials. There is no information yet about the nature of the powder.