He called 911.
Within minutes, he was hurried out of his house and men in uniforms were firing at the boat and someone was shooting back.
Police had used thermal imaging technology to see that a human form was under the boat's white plastic cover. They pounded the boat with flashbang grenades, a powerful concussive force, to see if the suspect would react; he barely did. Finally, an FBI negotiator on a bullhorn roused Dzhokhar and spent 25 minutes persuading him to come out. Local police cuffed the suspect, who was then taken by ambulance for medical attention to two gunshot wounds, likely suffered the previous night in the shootout with police.
After the arrest, Davis, exhausted but relieved, stood in the rain and looked back on four frenzied days of rugged, hurried and dangerous police work.
"Four days ago, my city was ruthlessly attacked," he said. "There's no explaining the savagery involved here. . . . I've spent the last several days looking at hundreds of hours of video tape. I got to see how brutal the attack was, over and over and over again."
More important, he said, he watched how first responders and ordinary citizens put people back together. "Tourniquets," Davis said. "Stemming the bleeding with their hands. Putting a man who was on fire out with their hands. These are the kind of things that came out of this savagery. It makes me proud."