A Pennsylvania college trustee apologized and announced his resignation Tuesday after a student found a 1980 yearbook photo in which the trustee wore a Nazi uniform costume.

Gettysburg College President Janet Morgan Riggs said in an email to the college community that Bob Garthwait decided to step down from the board of trustees.

A student brought the photo to the attention of a faculty member last week, and the administration was contacted. The student newspaper, the Gettysburgian, published an image of the photo, which depicts Garthwait in a military uniform costume with a swastika armband.

Riggs’ email quotes a message from Garthwait that says he dressed as a Nazi soldier in a POW camp as part of a “Hogan’s Heroes” TV show theme party at a fraternity.

Garthwait said that as a college sophomore, he “was not fully aware of the significance of those symbols.”

“My sincere hope is that our current students will learn from my poor judgment 38 years ago and be more thoughtful than I was about the impact of their actions on others,” Garthwait said in Riggs’ email. “I extend my sincere apologies to the entire Gettysburg College community, and I humbly ask for your forgiveness.”