By Brad Segall

HORSHAM, Pa. (CBS) — The FBI is now involved in an investigation looking into who sent an unauthorized e-mail to hundreds of Hatboro-Horsham High School students last week.

School officials are putting up a $500 reward for information that leads to an arrest and conviction.

The rogue e-mail that was sent out last week listed each student’s grade-point average and class rank. At this point, says assistant superintendent John Nodecker, it doesn’t appear that the district’s computer system was hacked.

“We believe that somebody extracted the data for legitimate reasons, and that somehow a person or persons got that secondary data and then put it into their e-mail and sent it out,” he told KYW Newsradio today.

Horsham police and the FBI are also investigating, to determine how the information was obtained and who sent it out.

Police say illegally obtaining the information and distributing it is a criminal act.

School officials believe there are students out there who have relevant information to help the investigation.