We determined CBP’s use of tear gas on these dates, in response to physical threats, appeared to be within CBP’s use of force policy. However, U.S. Border Patrol obtained an acoustic device and used it in an “alert tone” mode on November 25, 2018, which did not conform to CBP’s Use of Force policy because Border Patrol did not get advance authorization to have a device with this capability. CBP’s Use of Force policy would have permitted use of the alert tone in a manner reasonable and necessary for self-defense or the defense of another person in threatening, emergent situations. However, the policy does not authorize the carrying of any weapon for duty use that is not authorized, included on the Authorized Equipment List, or specifically approved by the LESC director. Using the acoustic device in alert mode may increase the risk of temporary or permanent hearing loss to those exposed to the sound and thereby increase the Government’s liability. CBP’s own internal investigation of the November 25, 2018 incident regarding the acoustic device was incomplete and inaccurate and did not provide all the information CBP needed to determine whether the CBP officer and Border Patrol agents involved had complied with the use of force policy. In addition, not all Border Patrol agents had the required training and certification to carry less-lethal devices. This occurred because Border Patrol lacked internal controls to ensure agents had fulfilled these requirements. Border Patrol agents using less-lethal devices for which they are not certified could result in unintended serious injury or death, increasing the Government’s liability. We made four recommendations to CBP to ensure compliance with its Use of Force policy and improve its investigative process. CBP concurred with all four recommendations.