Durham, N.C. — A murder trial began Monday for a Greensboro woman accused of killing a North Carolina Central University graduate student more than three years ago.

Shannon Elizabeth Crawley, 28, is charged with murder in the Jan. 4, 2007, shooting death of Denita Monique Smith, 25. Smith was shot in the head at Campus Crossing Apartments in Durham and then fell down a stairwell to the sidewalk, where a maintenance man found her body, police said.

Police arrested Crawley, a dispatcher for Guilford Metro 911 in Greensboro, five days later. They have said little about a possible motive for the shooting or the connection between the women.

According to a search warrant in the case, Crawley had been stalking Smith's fiancee, Jermeir Stroud, a Greensboro police officer, before the shooting. Crawley lived down the street from Stroud.

Crawley's first lawyer dismissed the love-triangle theory as the motive for the shooting and questioned both whether Smith was engaged and Stroud's role.

Prosecutors said they believe Crawley planned the killing and showed up late for work on the day Smith was killed.

Police said a woman matching Crawley's description was spotted leaving the apartment complex in a burgundy Ford Explorer. Investigators later searched a vehicle belonging to Crawley that matched that description.

The trial was first set for November 2008 but was delayed when tests on evidence didn't come back in time. The trial was again delayed in January 2009 when Crawley's attorney withdrew, citing an unidentified ethical concern. Crawley was assigned a public defender.

Friends and family of both Crawley and Smith packed a Durham courtroom Monday as jury selection began. The trial is expected to last two to three weeks.