LANSING, Mich. -

Video shot Thursday at the Michigan Capitol building in Lansing shows a group of people climbing through a first-floor window and closing it behind them.

The video is now part of an internal investigation into a security lapse at the Capitol on the same day the building was on lockdown after being flooded by demonstrators.

Read more: Right-to-work protestors arrested in Lansing

Michigan State Police responsible for security at the Capitol had blocked the entrance. However, the group somehow found a way inside.

"The concerns are that somebody is going to gain entry with a weapon -- some type of mace, a gun, a knife, whatever -- and that they have bad intentions," said former FBI agent and security expert Ned Timmons.

Local 4 showed the video to Timmons.

"Once they don't enter through the metal detectors you got a concern. What is their intent? What is their motive?" he said.

Timmons said beefing up security often comes down to budget.

"Obviously, economically, we can't put all these troopers out there everyday when nothing happens. So they responded and they handled the situation. I think they had some valid concerns for the security of the people inside and also the structural integrity of that building," he said.