The suspect in the mass shooting at a King Soopers supermarket in Boulder, Colorado that left 10 people dead is facing 43 more charges.

According to Fox News, the charges against suspect Ahmad Al Aliwi Alissa were filed on Wednesday by Boulder County District Attorney Michael Dougherty. 

It can be remembered that the 21-year-old suspect allegedly went on a shooting rampage in a King Soopers supermarket, killing 10 people, including the first police officer to arrive on the scene.

The suspect allegedly chuckled and laughed at himself as he went on a shooting rampage inside the grocery store.

RELATED ARTICLE: Colorado Shooting Leaves 10 Dead, Including a Police Officer

Boulder Shooting Suspect Faced More Charges

The 43 additional charges filed by the district attorney came after a month that Alissa went on a shooting rampage. The suspect was already charged with 10 counts of first-degree murder and one count of attempted murder in the attack.

Ahmad Al Aliwi Alissa reportedly used a Ruger AR-556 pistol similar to an AR-15 rifle when he opened fire at the supermarket last March 22.

The prosecutor's office requested that Alissa be charged with 33 additional counts of attempted first-degree murder, 10 counts of felony possession of a prohibited large-capacity magazine, and one count of first-degree assault.

Denver Post reported that among the attempted murder victims identified in the motion are seven civilians and 11 police officers, including slain cop Eric Talley, who was shot in the head and died.

The remaining nine people killed during the shooting were Denny Stong, 20; Rikki Olds, 25; Neven Stanisic, 23; Tralona Bartkowiak, 49; Teri Leiker, 51; Suzanne Fountain, 59; Kevin Mahoney, 61; Lynn Murray, 62; and Jodi Waters, 65.

With the additional charges filed by the DA, the Boulder shooting suspect now faces a total of 54 charges, 9 News reported. Alissa is set to appear in court again on May 25.

Boulder Mass Shooting

People hiding inside the grocery store said Alissa's violence had long intervals of silence when all they could hear was the automated announcements and music. The occasional ringing of a cellphone was also reported to be heard by people at the time.

During the spark of the shooting, hundreds of officers from around the Denver Metro area responded, including the SWAT. Despite the tragic incident, authorities said they have yet to identify the motive in the shooting.

The suspect's brother earlier described Alissa as very anti-social and paranoid. Alissa's brother said that the suspect turned anti-social when he experienced bullying in high school.

A teammate from his wrestling team, Dayton Marvel, said that Ahmad Al Aliwi Alissa was "kind of scary" to be around. Marvel went on to say that when the suspect lost his match, he quit the team and then yelled in the wrestling room that he would kill everybody.

"Our position is we cannot do anything until we can fully assess Mr. Alissa's mental illness," Kathryn Herold said during a court appearance. Herold is known to be Alissa's lawyer.

READ MORE: 17-Year-Old Suspect Arrested for Mass Shooting That Killed 5 People, Including Pregnant Woman

WATCH: Boulder King Soopers Shooting Suspect Lives in Arvada, Has Previous Assault Charge - From 9NEWS