Dimitrios Pagourtzis has remained behind bars at the Galveston County Jail since the deadly shooting on May 18.
Sources close to the case told Eyewitness News that the grand jury will be looking at the evidence this week.
The sources also say that the grand jury have already interviewed Pagourtzis' parents.
Eight students and two substitute teachers were killed when Pagourtzis allegedly opened fire during a first period art class.
Vigils and funerals were held this summer, along with safety meetings and the introduction of metal detectors at Santa Fe High School.
The Galveston County Jail will not release visitor logs to Eyewitness News, but we know several medical professionals are seeing Pagourtzis.
Admitted Santa Fe High School shooter, Dimitrios Pagourtzis, is being evaluated by a team of doctors hired by his defense team to find out why he opened fire on an art class, killing ten people on May 18. @abc13houston pic.twitter.com/KvNf6ycDIU— Shelley Childers (@shelleyabc13) August 6, 2018
His attorney, Nick Poehl, says the doctors were hired to try to answer the biggest question, why?
The team of doctors is looking at Pagourtzis' mental and physical state before the shooting. Doctors say there were no clear warning signs before "the wild behavioral change."
We've also learned Pagourtzis was not even enrolled in the first period art class where the shooting took place.
Poehl says the stack of evidence he has seen so far shows no signs of a hit list.
A court hearing is expected in the next 30 days, according to Poehl.
RELATED: Timeline: How the deadly shooting at Santa Fe High School unfolded