One of the suspected Dallas snipers was reportedly killed by a robot armed with a bomb.

At a press conference on Friday morning, Dallas police chief David Brown revealed that one of the suspected snipers involved in Thursday evening’s attack on police officers and protesters was killed after police detonated a bomb being carried by a robot in his vicinity. The decision to use the robot came after negotiations with the suspect broke down and police and the gunman began exchanging fire. “We saw no other option than to use our bomb robot and place a device on its extension to detonate where the suspect was,” Brown said. “Other options would have exposed our officers to grave danger.”

At the press conference, Brown also said that the deceased suspect said he was acting alone and was unaffiliated with any group. “The suspect said he was upset about Black Lives Matter. He said he was upset about the recent police shootings. He said that he was upset at white people. He stated he wanted to kill white people, especially white officers.” Before he was killed, the suspect also said that there were IEDs planted in the city, though no bombs have been found. Police have also indicated that the three other suspects in custody have been “tight-lipped.”