HOUSTON --The Houston Police Department is testing a white substance found in a letter at a west Houston school on Monday. A white powder was discovered around 10:45am Monday at John Paul II Catholic School in the 1400 block of Parkway Plaza Drive. Houston police, a Houston Fire Department HazMat team and a postal inspector were dispatched to the school to invesitgate the letter. Authorities are now testing the substance to determine what it is. Another envelope had been mailed to the school before. In the fall, someone sent powder filled letters to 17 Houston-area schools. Authorities put up a $100,000 for information leading to the person who sent the letters but never made any arrests. No other details were immediately available. Stay with Eyewitness News and abc13.com for the latest details.