"We're still dealing with discovery," Deputy District Attorney Carlo DiCesare said, adding that there is a lot of evidence to go through.
Michael Andre Hall, 23, and Steven David Carter, 34, both of Upland, have been charged with three counts of murder following the Nov. 26 shooting.
Police say Hall, Carter, Aaron Andrews, 25, and Albert Lamar Thomas, 25, went to rob Brandon Perez, 31 at his home in the 1000 block of South Magnolia Avenue. Perez and two of the suspected robbers were killed in a gun battle.
Hall and Carter pleaded not guilty to the charges.
Carter's brother, Russell Humes, 46, of Upland, has come to every court hearing since the suspect was arrested.
"I'm still in the dark, still trying to figure out what is going on," he said outside of the West Valley Superior courtroom.
Humes said Carter is a family-oriented man with a big heart and Hall was a "nice, young man." The two defendants know each other from around the neighborhood.
Hall and Carter are scheduled to return to court on Jan. 7.