A judge cited a conflict of interest Thursday while denying a public defender's request to represent a man charged in the grisly slayings of five people inside a San Francisco home.

Judge Lucy Kelly McCabe instead assigned a private attorney for Binh Thai Luc, who is charged with five counts of murder, with special circumstance allegations of committing multiple murders, robbery and burglary.

In addition, Luc received a special circumstance of lying in wait in the death of one victim, which would make him eligible for the death penalty if convicted.

McCabe told public defender Jeff Adachi that his office had a conflict of interest because it previously represented Luc's brother Brian Luc in a separate case last year, and the man might be a witness in the murder case.

Adachi reiterated his argument that Brian Luc is no longer considered a client after he was sentenced to three years of probation for drunken driving and firing a gun in a reckless manner.