The suspect was Oswald and the earlier victim was President John Kennedy.
Officer Tippet saw Oswald walking along a sidewalk and focused on him as the suspect based on a general description of the suspect. Oswald shot Officer Tippit 3 times in the chest after he exited his patrol vehicle and then administered a coup de gras to the temple while Officer Tippit lay prone in the street.
Officer Tippet was buried on the same day as President Kennedy and Oswald.

The major media outlets will not tell you about Officer Tippit's involvement nor his death on that day 50 years ago...but I thought that you should know...
http://www.dallasnews.com/news/jfk50/re ... -flash.ece
http://www.jdtippit.com/