The Massachusetts State Police reportedly tested a robot dog produced by Waltham-based Boston Dynamics for three months from August to November.
According to CNN, the robot—named "Spot"—joined the police department's bomb squad to see how it would function in a situation where there are bombs and hazardous materials or dangerous suspects.
The American Civil Liberties Union of Massachusetts has raised questions about the use of such technology, and accused the agency of conducting the test program "in secret."
"We need to have transparency and safeguards to ensure that law keeps pace with technology and technological innovations. This kind of technology shouldn't be deployed in secret," said Carol Rose, executive director of the American Civil Liberties Union of Massachusetts.
The lease agreement between the agency and the company specifically prohibited the robot being used in any way that would "physically harm or intimidate people."