By STEVEN LONG

February 26, 2002 -- HOUSTON - Andrea Yates thought about using a knife to kill her five children, but decided stabbing was "too bloody," a jail psychiatrist testified yesterday.

Yates, who drowned her kids one at a time in the family bathtub last June 20, also rejected drugs as a way to kill them, Dr. Melissa Ferguson said under cross-examination at her murder trial.

"Do you remember her making a statement, 'After thinking about my options, I decided drowning would be the best way to end their life' ?" assistant District Attorney Kaylynn Williford asked.

Yates said "something about drowning, that drowning was the way," replied Ferguson, who began a six-day interview with her at Harris County Jail on June 21, the day after the drownings.

Asked by the prosecutor if she recalled her saying, "I decided a knife was too bloody," Ferguson said yes.

Yates, 37, has pleaded not guilty by reason of insanity to two charges of capital murder.

But prosecutors contend Yates called 911 after killing her children because, even though she suffered from a mental illness, she knew what she had done was wrong.

It is a pivotal issue in the trial because in Texas, the prosecution does not have to prove Yates was sane - only that she knew right from wrong when she drowned her youngsters.

Ferguson, who said Yates was psychotic from postpartum depression, said she did not believe Yates knew the difference between right and wrong when she killed her four sons and baby daughter.

Yates thought she was doing the right thing, said Ferguson, who on Friday testified that the former nurse believed she was Satan and that her kids had to die to be saved from hell.

"She was convinced the children were going to be tormented [by Satan] the rest of their lives and they were going to perish in the fires of hell," she said yesterday. "She suffered a serious mental illness."

Yates thought about drowning her children the night before she killed them, the psychiatrist testified.

John Bayliss, a nurse at the jail's hospital unit, testified that, a day after the drownings, Yates asked to be allowed to attend the memorial for her children.

He said she appeared to be "internally occupied" and thought she may have been hearing voices in the weeks after she was jailed.

"She was a person who wasn't connected with reality at all," he said.

Her demeanor in jail has improved dramatically over the last few months since she's been taking medication, he said.

Russell "Rusty" Yates, who is standing by his wife, is expected to testify on her behalf and has not been allowed in the courtroom.

He was spotted at the court yesterday trying to keep busy and pass the time playing the computer game Tetris. With Post Wire Services