BARABOO, Wis. (AP) -- The attorney for the father of infant twins found dead in Baraboo says his client takes "behavioral medication" and without it, may not be competent to deal with the legal system.

Lawyer Paul Polacek says he's not confident David Yates will be able to make the right decisions. Yates is in the Sauk County Jail on a probation hold.

Five-week-old Savannah and Tyler Yates were found dead at their father's house Sunday. Yates was found in bed.

Preliminary autopsy findings have caused police to investigate the deaths as homicides.

The twins' mother, Susan Winbun, doesn't live with Yates and says she left the babies with him only when she had to work.

The infants were the second set of Winbun's twins to die in infancy. Winbun says twins born to her 14 weeks early in the late 1990s died of natural causes after only a few days.

(Copyright 2008 by The Associated Press. All Rights Reserved.)