Prosecutors did not call any rebuttal witnesses and closing arguments are scheduled for Oct. 11, The Hartford (Conn.) Courant reported.
Komisarjevsky faces the death penalty if convicted of killing Jennifer Hawke-Petit and her daughters Hayley, 17 and Michaela, 11, during a July 23, 2007, home invasion robbery and arson at their Cheshire home.
The defense rested its case after prosecutors ended their cross-examination of Dr. Leo Shea, a key defense witness, the newspaper said.
Shea, a New York neuropsychologist, had testified Wednesday that mild traumatic head injuries and sexual abuse Komisarjevsky suffered, in combination with his drug use, resulted in "a perfect storm" that impaired Komisarjevsky's cognitive ability.
Shea acknowledged "perfect storm" does not necessarily lead to criminal acts.
"It doesn't necessarily lead to criminal behavior. I would agree with that. It predisposes him to it," he testified.