Jeffrey L. Dahmer's lawyer hinted at an insanity plea by the alleged serial killer at a hearing set for Tuesday on 15 counts of murder.
Police have said Dahmer, 31, has admitted killing and dismembering 17 males since 1978. He has not been charged in two of the slayings.Defense attorney Gerald P. Boyle did not return calls Monday but said last month he was investigating Dahmer's state of mind at the time of the slayings.
"There's a question as to when these offenses were being committed, if he had a mental disease or defect," Boyle said.
Dahmer was to enter his plea Tuesday.
Under Wisconsin law, he would have a two-phase trial if he pleaded not guilty by reason of mental disease or defect.
In the first phase, a jury would decide whether he committed the offenses; if the verdict were guilty, the jury would decide in the second phase if he was sane at the time.
The murder counts each carry a mandatory sentence of life in prison.
A partially handcuffed man led police to Dahmer's apartment on July 22, saying he had been threatened there. Police found remains of 11 victims, including heads in the refrigerator and skulls in boxes, court documents said.