UNION, S.C. (AP) _ Susan Smith is competent to stand trial even though she suffers from a mental disability that could have played a role in the drownings of her two young sons, a newspaper reported today.

A recently completed evaluation by the state Department of Mental Health says Ms. Smith's disability includes severe depression, but she is not insane, unidentified sources told The (Columbia) State.

Police say Ms. Smith, 23, confessed to driving her car into a lake with her two sons strapped into their car seats. Her murder trial begins July 10, and she could get the electric chair if convicted.

A verdict of not guilty by reason of insanity would send her to a mental hospital until doctors and a judge found her sane. A verdict of guilty but mentally ill would mean she could be sentenced to life in prison or death.

Defense attorney David Bruck says he probably will pursue a defense that hinges on her mental state at the time.

On Wednesday, investigators dredged up painful memories for residents when they rolled Ms. Smith's car into murky lake waters to re-enact what her two boys may have seen in their final moments.

``She confessed to killing them,'' said Kellie Allen, who said she knew Ms. Smith as a child. ``Who cares how long it took for the car to go underwater? We don't need to hear that kind of stuff.''

It took about six minutes for the burgundy 1990 Mazda Protege to sink with a waterproof video camera in the back seat. As news helicopters hovered overhead, the trunk lifted high into the air before it slid under the surface with a rush of air bubbles.

``Those helicopters brought back bad memories this morning,'' said Linda Williams, who lives near John D. Long Lake.

``With O.J. and his mess on TV every day, we hear enough gory details without knowing how long those children suffered before drowning,'' she said. ``I just don't need to go through that.''

Some may have to. The camera may be used by prosecutors during Ms. Smith's trial to show what 3-year-old Michael and 14-month-old Alex saw as the car sank.

Investigators solemnly watched as one of them released the car's hand brake, closed the door and let it roll down a boat ramp into the lake. As the car sank, divers took photographs and investigators videotaped it from several angles on shore.

The car floated a distance and came to rest upside down, much as divers found it Nov. 3 after Ms. Smith confessed, said State Law Enforcement Division spokesman Hugh Munn.

Munn would not say how deep the water was where the car sank. The vehicle was pulled out after about 90 minutes.

Sheriff Howard Wells stood grim-faced on the bank. ``We found that there were several questions during this investigation that needed to be answered before the trial, and a re-enactment was the only way we could do it,'' he said, refusing to elaborate.

In her confession, Ms. Smith said she was suicidal the night of Oct. 25. She never explained, however, why she got out of the car and let it roll into the lake.

She originally told investigators that a carjacker had taken the boys. That touched off a nationwide search that ended when she confessed nine days later.