A Rochester man charged with attempted murder for allegedly assaulting a woman with a hammer was ordered to undergo a mental illness and cognitive impairment screening.

Joseph Ndichu Kinyanjui, 65, is charged in Olmsted County District Court with four felonies — first-degree attempted murder-premeditated, second-degree murder-without intent, first-degree assault and second-degree assault with a dangerous weapon. He has been held on $500,000 conditional bail since his first appearance on May 10.

Kinyanjui was found competent to proceed on Jan. 6, but the following day Judge Kathy Wallace filed an order for examination. The order states that Kinyanjui has pleaded not guilty “by reason of mental illness or cognitive impairment” and that he intends to offer evidence of mental illness or cognitive impairment at trial.

Kinyanjui had previously been evaluated to determine if he was competent to proceed to trial but no opinion had been made “as to whether, because of mental illness or cognitive impairment, the defendant, at the time of committing the alleged criminal act, was laboring under such a defect of reason as not to know the nature of the act or that it was wrong,” the order read.

Police were called to a house in the 5100 block of 54th Avenue Northwest at about 7 p.m. on May 8 where a 40-year-old woman and her daughter were waiting outside. The woman told police her father was assaulting her mother, Rochester Police Capt. Casey Moilanen said a day after the incident.

Police entered the house and heard noise coming from a bedroom. The door was locked, but officers were able to kick out a panel in the door. Through that broken panel, Moilanen said, they saw the victim on the floor covered in blood. They tased the suspected assailant, who resisted arrest, and eventually took him into custody.

The 66-year-old woman was transported to Mayo Clinic Hospital–Saint Marys with head trauma and multiple significant injuries. She was in and out of consciousness at the scene and was able to talk to officers, Moilanen said.

Kinyanjui was also taken to Saint Marys for medical clearance before being taken to the adult detention center.