Police investigate the scene after Deputy U.S. Marshal Christopher David Hill was killed when a gunman opened fire on law enforcement officers serving an arrest warrant inside a home earlier in the area, Thursday, Jan. 18, 2018, in Harrisburg, Pa.<br>Dan Gleiter/PennLive.com via AP

Officials piece together chaotic events after officer killed

Investigators are working to piece together the chaotic sequence of events that led to a deputy U.S. marshal being shot to death while serving an arrest warrant in Pennsylvania's capital city.