Published: Aug 23, 2011 10:24 PM EDT
Updated: Aug 23, 2011 10:50 PM EDT

FORT MYERS, Fla.- Matthew Gullett has been waiting two years to face a jury for the murder of his girlfriend, Shannon Sweet.

Cape Coral police say Gullett strangled Sweet and left her body in an apartment complex shower to decompose for six days. But just before his scheduled trial this month, new DNA evidence was discovered on Sweet's neck, and it points to Tyson Richardson, not Matthew Gullett.

He died in the Steak and Shake shootout in Cape Coral months after Sweet's death. Her mother Vicki Shepard told us by phone, that doesn't mean Gullet is innocent.

"Matt already confessed more than once that he did it. I don't see where other DNA is going to link anyone else to this," she said.

Gullett's lawyers think otherwise. They've hired experts to investigate how Richardson and Sweet knew eachother.

Richardson and Sweet were both known drug users. Now prosecutors want to figure out if they had any contact the day she died.

Still, the Sweet family says they know Gullett is guilty, it may just take longer now to prove.

"I never had a chance to say goodbye to Shannon. I'll always hold that against him. I know he did it," said Shepard.