Simon served as counsel for the now-acquitted Amanda Knox who was initially convicted of murder by an Italian court.
Porter, who is studying abroad, is accused along with two other American students, of setting off Molotov cocktails during the protests. Egyptian officials have detained all three, claiming they clashed with police.
Porter's family confirmed to NBC10's Rosemary Connors that they are now working with Simon.
Gregory Porter, 19, is from Glenside, Montgomery County, Pennsylvania and graduated from LaSalle College High School. The school president described their community as "in shock" on Tuesday.
"He's a bright young man, no question about it," said Brother Richard Kestler. He insists Porter was a wonderful student who was never in trouble.
On Porter's Facebook page, friends have left messages and well wishes for his safe return. At his Alma Mater, prayer services are on hold -- they're hopeful Porter will be back home soon.
"Maybe after the holiday, but not right now," Brother Kestler said. "We'll just have a celebration that he's returned."