CLEVELAND -- Cleveland Police continue to search for a young man who's been missing since a concert Friday at Progressive Field.

Cory Barron was last seen about 9:30 Friday night in section 468, where Jason Aldean headlined a country concert with more than 40,000 people inside.

After five thorough searches, police are convinced Barron is no longer inside the stadium. Monday they concluded a ground search of downtown Cleveland with no results.

Cleveland Police Department Third District Commander Patrick Stephens says no one is sure what happened to Cory.

Kent Weaver grew up with Cory Barron in Fremont. He says Barron is a big Indians fan and knew Progressive Field well. "That wasn't unfamiliar territory."

Running off? That isn't something that Cory Barron would do.

"He wasn't that type of kid, just to run away," said Weaver. "He was very close with his family. Very loved."

Barron went to the concert Friday with a group of friends. He got up to visit another section of seating, and perhaps get a drink, and he hasn't been seen since.

"Last I knew, he went to go get a drink and they haven't heard from him since," said Weaver.

Police say it doesn't add up. Monday they worked through the landscape trying to eliminate areas, working from most likely to least likely spots.

They've used heat-sensing helicopter to search from the air. They've checked hospitals, jails, waterways, just about anywhere Cory Barron could be. Now the progress moves to more detective duties, less physical searching.

Cleveland Police say Barron's cell phone is being monitored for activity, which has not happened since Friday.

His friends are on twitter, and the hashtag #HelpFindCory, which police say has already generated new leads.

Barron is 6 foot 2, weighs 225 pounds, with brown hair and blue eyes. He had jeans and a Budweiser teeshirt on Friday.

If you have any information you're asked to call Cleveland Police at 216-623-5300.

Follow WKYC's Sara Shookman on Twitter: @SaraShookman