Police are searching for a man who they believe may have been the last person seen with missing University of Virginia student Hannah Graham.

Graham was spotted in a bar with an older man on the night she went missing and it is believed that she got into a car with the same man and left the bar.

The identity of the man has not been released, but police are hoping he can answer some questions about the whereabouts of Graham.

Arrest Warrant Issued for Missing Student Person of Interest Traffic Violation http://t.co/VlepbKc8yi pic.twitter.com/1Ktuv5wEse

— Good Morning America (@GMA) September 22, 2014

“Police spoke to him this morning when they executed a search warrant and seized his car, but did not feel that they had enough probable cause to arrest him,” Charlottesville Police Chief Timothy Longo said.

“We know that he purchased alcohol (in the restaurant) and we know that Hannah Graham was with him. We also know that within 15 minutes he was gone from that bar and Hannah Graham was with him,” he continued.

“People saw Hannah and people saw him, and people saw them together. And it’s entirely possible, we believe, that Hannah Graham may have gotten into his vehicle,” the chief added.

All surveillance videos showing missing UVa. student Hannah Graham http://t.co/GJgaYv9rng Call 434-295-3851 w/ any info.

— CBS 6 WTVR Richmond (@CBS6) September 23, 2014

Police are asking anyone who may have witnessed Hannah get into the man’s car to come forward and said that the man was not taken into custody after he was questioned.

Have you. or someone you know, seen anything that could help bring Hannah Graham home?http://t.co/evrq31igkR pic.twitter.com/PvI5sJiGcY

— Dateline NBC (@DatelineNBC) September 22, 2014

Police said the man has not been named as a suspect, but they know who he is and where he is and are not finished questioning him.

Police have questioned several other people about the disappearance of the young woman and are continuing to search for her.

The police chief would not say if he thought Hannah was still alive but did say that he was hopeful and would not give up until she was found.