BISMARCK, N.D. – The North Dakota Private Investigation and Security Board is investigating the use of dogs last week by private security guards at the Dakota Access Pipeline construction site.

The board also is investigating whether the security personnel were properly licensed or registered to operate in North Dakota, said Monte Rogneby, the board’s attorney.

“The board’s primary responsibility is to protect the public,” Rogneby told Forum News Service Friday. “The board takes that responsibility very, very seriously.”

The board, which licenses and regulates the private security industry, has received complaints about the guard dogs used on Sept. 3 at a pipeline construction site in Morton County, Rogneby said.

Pipeline opponents rushed a construction area west of Highway 1806 where crews were bulldozing land the tribe had identified as containing burial grounds and other sacred sites. Some reported being bit by guard dogs used by the security officers, and video captured by Democracy Now! shows a dog with blood on its mouth. Dakota Access, which says no sacred sites were destroyed, has declined to answer questions about its security personnel.

The complaints to the board include a petition signed by more than 100,000 people on MoveOn.org calling for the board to investigate.

Matt Hildreth, a Brookings, S.D., native with friends and family along the Dakota Access route, launched the petition Monday after watching videos on social media of the guard dogs, including instances where he said the handlers appeared to direct the dogs to attack.

“By turning their dogs loose on protesters, the security guards hired by Dakota Access LLC acted in a reckless and inhumane manner,” the petition states. “The guards had no uniforms, drove vehicles with out-of-state plates, and appeared to have little or no training.”

Hildreth said the initial people to sign were his friends and family, but soon “it went viral,” hitting 116,000 on Friday afternoon.

“There are so many people watching what’s going on in North Dakota,” said Hildreth, 31, who has a background in social media marketing and recently moved to Ohio.

The Private Investigation and Security Board has two staff members and a governor-appointed board of volunteers with expertise in the security industry.

The board requires that private security be licensed or registered as independent contractors of a licensed agency. Providing security services without being properly licensed or registered is a criminal offense, Rogneby said.

At this time, the board has not confirmed who the security personnel working on Sept. 3 were or whether they were properly licensed and registered, he said.

The board does not have any specific rules related to the use of dogs. However, the board will use in its investigation the legal standard in North Dakota’s criminal code that outlines when force can be used to protect individuals or property, Rogneby said.

The board has a variety of ways to enforce the law, including issuing fines, suspending license holders and taking civil action, Rogneby said.