after boot camp, after september 11th, ronald wanted to defend his country, though his mother worried he might die overseas. >> i honestly didn't want him to go. >> reporter: before his deployment, he came home to visit his girlfriend, he was planning to propose to her. that weekend ronald arrived at his mother's home, he was confronted by gang members just outside the house. moments later, there were gun shots. one of those bullets was fatal. ronald brock was just 19 years old. >> and we know that mr. brock or believe that mr. brock was not armed when he was killed. >> reporter: detective dwayne fields supervises the gang unit. he said his brother angel was the actual target. >> ron brock was wrong place, wrong time. >> wrong place, wrong time. his brother was a gang member. he had his head shaved because he's united states marine corps and united states marine corps shaves their heads. and most of the thugs out here, most of the gangsters out here