LA CROSSE, Wis. (AP) _ An elderly woman, her son and his girlfriend found shot to death at the woman's home were apparently killed by a burglar, police said Saturday.

Lt. James Schleifer said he believed the home of Lila Bush, 73, was randomly chosen and that the slayings were not premeditated.

''It started out as a burglary from appearances and became a robbery,'' he said. ''The homicide was seconday.''

The bodies of Mrs. Bush, her son Kenneth K. Bush Jr., 32, and his girlfriend, Debra K. Reget, 35, were found Friday morning by a family member, police said. An undetermined amount of money was stolen from the home, police said.

The assailant entered the home apparently sometime Thursday evening or early Friday morning by forcing a basement window, Schleifer said.

All of the victims had been shot with a small-caliber handgun, but Schleifer said he did not know the caliber of the gun nor how many times each victim was shot. Autopsies were planned at the State Crime Laboratory at Madison.

Police have ''no named suspects in the case. But we have numerous leads we're pursuing,'' Schleifer said.

Bush was living with his mother at the time of the incident, but Schleifer said he did not know where Ms. Reget was living.

No one in the neighborhood had been found who saw or heard anything unusual Thursday night, he said.