CEDAR RAPIDS - A Cedar Rapids man was convicted Thursday of first-degree murder for killing two 18-year-old women.

Kyle Marin, 21, faces life in prison for the deaths of Molly Edmondson and Katrina Hill, whose bodies were found beaten and stabbed in April at Edmondson's Cedar Rapids apartment.

Marin admitted to the killings but claimed that mental illness, alcohol and medications - including the antidepressant Zoloft - clouded his judgment.

Linn County prosecutors accused Marin of returning to the apartment after a party, making the cousins get naked in the shower and attacking them. Marin, in his statement to police the night of the killings, said he confessed partly because he deserved punishment.

"The question is, what punishment?" defense attorney Tom Diehl told the jury during closing arguments.

He said Marin was acting on an impulse that he could not control due to adverse side effects of Zoloft and Buspar, an anti-anxiety medication. One country has even banned the use of Zoloft for people Marin's age, Diehl said.

Diehl said the case is less about the insanity defense - which he urged the jury to consider - but more about whether Marin had the mental capacity to be convicted of first-degree murder.

Linn County Attorney Harold Denton told the jury how the prosecution proved that Marin was not insane. He said Zoloft carried a warning pertaining more to suicide than homicide.

"Ladies and gentlemen, Zoloft and alcohol did not take the lives of those two women," he said.

"He was able to resist (suicide), wasn't he? What he wasn't able to do is resist killing."

The jury reached the verdict after deliberating about 3.5 hours.