The D.A.'s office said investigators received the DNA hit three weeks ago.
With his wrists cuffed in front of him, Jesse Perez Torres, 35, appeared in court for about 20 minutes Thursday, but his arraignment was moved to Nov. 16. The decision to delay it was made to give the defense attorney more time to review the case.
The Long Beach man is charged with one count of first-degree murder with a special circumstance allegation of kidnapping in the death of Lopez.
Prosecutors said the charge could carry the death penalty but they have not decided whether to seek it.
It took the D.A.'s office six days to file charges.
"We took additional time on this case because it's such an important case to our community," Riverside County Deputy District Attorney Mike Soccio told members of the media outside the courtroom Thursday.
"When we're dealing with DNA, there's always a lot of information that, just because there might be a DNA hit, all that does for us is point out a possible suspect," he said. "With so much additional information, by the time we received the paperwork in the case, there just wasn't time to make a fully-reasoned decision to file."
Soccio said there was additional evidence against Torres in the case, but wouldn't specify what it was.
On July 15, 2010, the 17-year-old girl was walking to a friend's house after attending summer classes at Valley View High School in Moreno Valley when she was abducted. Her body was found five days later in a remote field about 2 1/2 miles away from the school.
At the time of the crime, Torres lived across the street from the school, but prosecutors said he moved out a month later to Long Beach. He was arrested during a traffic stop a week ago.
