The FBI has joined the search for missing Irish American student Shane Montgomery, last seen in Kildare’s Irish Pub in Philadelphia on Thanksgiving eve.

Shane Montgomery is described as a 5’11 white male, about 130 pounds, with short brown hair and green eyes. He has a tattoo of a Celtic cross on his shoulder blade.

The FBI interviewed the staff at the Irish bar at which Montgomery, a West Chester University student, was escorted out of early on Thanksgiving morning after he accidentally tripped into a DJ booth.

Both Montgomery’s cousins and bar staff say he was not over intoxicated and apologized before he left for the incident.

“The bouncer spoke to him and Shane apologized and left," an investigator said. "There is no indication that he was staggering."

Hundreds of people also gathered in Manayunk, a historic neighborhood in Philadelphia, on Saturday night to light candles and pray for the missing college student. A special Mass followed at St. John the Baptist Church on Rector Street.

The 21-year-old Went to Kildare’s Irish Pub, a neighborhood bar, to meet with friends there on Thanksgiving Eve.

Nearly 500 people, including friends, family, fellow students, and neighborhood residents, have searched the streets and the Schuylkill riverbank over the last few days.

According to Philly.com, the search party was among the largest ever assembled and managed by Greater Philadelphia Search and Rescue.

On Saturday evening, supporters lit candles in a park across from the pub where Montgomery was last seen at about 1:45 early Thursday morning.

"It's really scary," said Katie Kavanaugh, 21, a student at Pennsylvania State University who grew up with Montgomery. "It's something you hear about on the news and you never think will happen to you. I'm trying to hope for the best but ready for whatever the outcome may be."

He had been at the bar with a cousin and friends and they became separated.

Kildare’s Irish Pub lies across the street from the Manayunk Canal, and Philadelphia police dispatched officers from a marine unit to patrol the waters. They found nothing.

"Every once in a while, there's a burst of hope," said Shane’s mother, Karen Montgomery, "but a part of me knows something is wrong."

She said she was touched by the outpouring of concerns for her son.

"You hear about the bad in the world, but this support has been overwhelming, and I appreciate it."

Shane’s father, Kevin Montgomery, said he is heartbroken.

"We're praying for a turning point or clue that points us in the right direction," he said. "We won't stop until we do."

The family has offered a $10,000 reward for any information about Shane Montgomery’s disappearance.

Friends and family have posted fliers and social media messages, while police have searched the river and used a helicopter on Friday to check rooftops and fire escapes, Philly.com reports.

He was last seen wearing a gray button-down shirt, blue jeans, a gray hooded sweatshirt, and black sneakers.

The last location tracked on his cell phone was a CVS pharmacy at 2:38 a.m. Thursday.

Anyone with information is asked to contact Detective Patrick Valentino at 215-686-3353 or 3354.