The legal team for a Colorado teen boy charged in the death of a 20-year-old woman may blame his acne medication for her violent murder.

Aiden von Grabow, 15, is accused of stabbing Makayla Grote to death with a hunting knife Nov. 18 at her Longmont home, according to the Longmont Times-Call.

Authorities suspect that the teen went to the house to kill Grote’s younger sister, whose name was allegedly first on his hit list, but attacked the 20-year-old when she answered the door.

In a hearing Friday, Grabow’s attorneys appeared to be laying the groundwork to argue Accutane, a drug prescribed to treat acne, played a role in the murder.

The defense petitioned to call on a psychiatrist, who studies the effects of Accutane, as a witness at a March 5 hearing that will determine whether the 15-year-old will be tried as an adult, according to Longmont Times-Call.

His lawyers said they planned to call on Dr. Doug Brenner, who could testify that the drug can cause aggressive behavior.

Boulder District Judge Andrew MacDonald, however, sided with prosecutors who reportedly objected to the psychiatrist being called on as a witness. MacDonald said Friday that he agreed the physician was not relevant to the transfer hearing.

If the case goes to trial, however, the psychiatrist could possibly take the stand.

The hearing next week will also decide whether there is sufficient evidence for the case to be tried.

The 15-year-old suspect also faces charges of attempted murder for alleged plans to kill Grote’s younger sister and two others on his supposed hit list.