David Brown, the Dallas police chief, recounted the hours of negotiations that were conducted but failed when a suspect at the El Centro College in Dallas was cornered by the police. They sent a robot that could detonate a bomb and blow up the suspect.

Said Brown at a Friday morning press conference: "We saw no other option but to use our bomb robot and place a device on its extension for it to detonate where the suspect was. Other options would have exposed the officers to grave danger."

The suspect had been hiding in the El Centro College parking garage for a long time Thursday. Finally, the cops closed into his den and took action to "blast him out," according to Mayor Mike Rawlings Friday. The police were not able to work out the negotiations with the suspect, and it had been put on hold.

The man was thought to be Micah Xavier Johnson, 25, of Dallas, said a senior law enforcement official to NBC News.

The suspect had explained to the cops that he was unhappy about the shootings and was eager to kill whites, "especially white officers".

The mayor agreed that Johnson was bombed out by the robot. He ruled out the possibility that he may have killed himself.

Reports say that the process had been "jury-rigged with a claymore and a cheap surveillance bot" This device is called MARCbot (Multi-Function Agile Remote-Controlled).

Peter W. Singer, a technological warfare expert and author of "Wired For War," said that the mobile robots were recorded as having been used in the early days of the Iraq War. However, it has not been used in domestic policing.

The robots are used for observation or dismantling purposes. Law enforcement can even use them when officers are threatened by impending danger.