Ann Arbor — Richard Sheridan was glancing around Michigan Stadium and happened to look up during Michigan’s season opener last Saturday night, when something strange caught his attention.

Sheridan, a season-ticket holder, spotted a drone. It is illegal to fly drones on the University of Michigan campus. There were two individuals arrested for the drone activity, according to Melissa Overton, the University of Michigan deputy chief of police. The ordinance violation was reported Saturday at 10:17 p.m.

“We made contact with the drone pilots that night and made two arrests,” Overton told The Detroit News.

The investigation remains open, Overton said.

“There’s a lot to it,” Overton said. “We’re going to continue following up on all our leads and do everything we can do.

“It’s difficult to control air space.”

According to the University of Michigan policy on the operation of drones (unmanned aircraft systems or UAS), penalties for “unsafe or unauthorized” use of a drone by anyone on the Michigan campus may include “criminal and/or civil penalties.” It also can be recommended that the violator loses flying privileges for a year on the first transgression and a permanent loss if it’s repeated.

After Sheridan’s initial shock, he realized what he was seeing in Michigan Stadium, which had an announced crowd of 110,811 for the Wolverines’ season opener against Middle Tennessee State.

“We looked up, we saw it, it was hovering there, and at first I thought, ‘’Is this part of the television coverage? Is this a new way they’re filming?’” Sheridan told The News. “It hovered in the south end of the stadium for what felt like a couple of minutes to me. It wasn’t doing anything threatening per se. It wasn’t swooping or anything like that. It was literally hovering there and then went over Stadium Boulevard and disappeared.

“You’re looking at it and you realize, ‘Oh my gosh, it’s a drone.’ It wasn’t a teeny-tiny drone, it wasn’t a huge drone, either, and whoever was controlling it was actually doing a pretty darn good job. Those things can be challenging at times, but it was just hanging there.”

Sheridan posted a photo of the drone on Twitter Saturday night at 10:19 p.m. and posed this question: “Legal?”

Drones fly unmanned and are controlled from the ground.

“It felt weird and unnerving is the best way to put it,” Sheridan said. “It didn’t feel right. Even if it was nothing nefarious in their intent, they were just having fun, you could lose control of it and it can hurt somebody.”

The Michigan Department of Public Safety and Security on Aug. 29 released a statement that on Fridays before the seven home football games this season, “people at or near Michigan Stadium may see a drone flying overhead. No drone activity will occur on the day of a home football game.” It cited the Regents’ Ordinance exceptions that includes law enforcement purposes.

According to the release, the drones will fly predetermined routes but will not be flown over occupied residential buildings.

Overton said she could not share much information because the investigation remains open but did say the department remains vigilant at all times.

“The safety of everyone there is important to us,” she said. “That’s a big thing.”

A spokesman for the UM athletic department referred all questions about the incident to UM Police.

Michigan plays Army on Saturday at noon at Michigan Stadium.

achengelis@detroitnews.com

Twitter: @chengelis