A man accused of killing 10 people at a Colorado supermarket is still mentally incompetent to stand trial, a judge has ruled.

       Ahmad Al Aliwi Alissa, 22, allegedly gunned down a police officer, grocery workers and customers inside and outside the store in Boulder last year during a shocking spree of violence.

       His prosecution has been on hold since December 2021 when Judge Ingrid Bakke ruled that he is unable to understand legal proceedings and work with his lawyers to defend himself.

       The suspect’s mental evaluation has not been made public, but in court documents it was stated that he had been provisionally diagnosed with an unspecified mental health condition that limits his ability to “meaningfully converse with others.”

       Investigators have not stated the motives for the suspect’s attack or why the King Soopers supermarket was targeted.

       Ahmad Al Aliwi Alissa has been charged with 10 counts of murder

       (EPA)

       Mr Alissa lived in a neighboring suburb in the city and had passed a background check to buy the Ruger AR-556 weapon used in the attack.

       The judge has set a 21 July hearing for a further evaluation of the suspect’s ability to stand trial.

       Boulder police Officer Eric Talley, a 51-year-old father of seven, was shot and killed as he ran towards the store after arriving at the scene of the violence.

       The nine others killed inside and outside the supermarket were Denny Stong, Neven Stanisic, Rikki Olds, Tralona Bartkowiak, Teri Leiker, Suzanne Fountain, Kevin Mahoney, Lynn Murray and Jody Waters.

       The supermarket re-opened in February, with half of the staff who worked there at the time of the shooting choosing to return.