The Moments Before College Student Shane Montgomery Disappeared

— -- A college student disappeared on Thanksgiving after drinking with friends at a Philadelphia bar, and police have found no trace of the missing college senior.

The FBI is also involved in the hunt for Shane Montgomery, 21, who was last seen at an Irish pub around 2 a.m.

Here's what police know about what happened on the night Montgomery disappeared:

9 p.m., Nov. 26: Montgomery, a student at West Chester University, and his cousin headed out the night before Thanksgiving around 9 p.m., police said.

"He left his cousin's house, which is near Main Street in Manayunk," Officer Jillian Russell, a spokesperson for the Philadelphia police department, told ABC News today. "They stopped at different bars before a last stop at Kildare's pub."

1:45 a.m. on Nov. 27: Montgomery was last seen around 1:45 a.m. at Kildare's Irish Pub. He was wearing a gray button-down shirt, a gray hoodie, blue jeans and black sneakers, police said.

Montgomery left the bar on foot after bumping into a table, but witnesses say he wasn't drunk, according to police.

2:30 a.m. on Nov. 27: Montgomery's cell phone sends a ping from near a CVS Pharmacy less than a mile from the bar, ABC News' Philadelphia affiliate WPVI reported.

Nov. 28: Montgomery's family reports him missing. Police continue to search the Philadelphia area, but have found no sign of the missing student, and say he has not appeared on any surveillance video.

"There's not even one person that we are keying on at this point," First Deputy Police Commissioner Richard Ross said.

The FBI got involved in the search over the weekend, police said.