Gabriel Lopez, 20, and Alejandro Sanchez, 19, are charged with first-degree murder.
Authorities believe Lopez stabbed Perez, who was his girlfriend, after an argument. They say Sanchez was present during the murder.
Perez's body was found early Saturday morning floating near the edge of Jordan Lake after a fisherman called 911.
- Caller: We see dead people in the water.
911 Operator: you see what?
Caller: Dead people.
911 Operator: You see dead people?
Caller: [sic] Yes, I'm so scared, so we call 911 now.
ABC11 Eyewitness News learned in court Monday that Perez was stabbed 30 times.
An eyewitness sent images to ABC11 of Sanchez at the scene with authorities on Monday. The Chatham County district attorney refused to comment on what Sanchez was doing there but said the investigation is ongoing.
Those who knew Perez are heartbroken and her family is too distraught to talk to reporters. She lived with her mother and siblings in Fuquay-Varina.
Perez recently graduated from Four River Oaks Middle School in Raleigh and was scheduled to begin her freshman year at Fuquay-Varina High School this year.
A counselor from River Oaks, who knew Perez, says she is in disbelief.
"I was like, not my Pattie, I really couldn't believe it that it happened," Counselor Jamie Burgins said. "I just wondered who would, who would do something like this to such a sweet girl with so many ambitions, so many goals? She was really looking forward to high school."
Friends set up a Facebook page in memory of Perez, to visit the page, click here.
Perez's funeral will be held at Williford Funeral Home on Thursday.