Supreme Court limits use of "bad acts" testimony

The Nevada Supreme Court on Monday imposed tough, new restrictions on prosecutors using evidence of prior "bad acts" to help convict a defendant.

An appeal was filed on behalf of Lonnie Ray Tavares, who was convicted of murder in the death of his and his girlfriend's 3-month-old baby. The opinion points out that, because there was no direct physical evidence or eyewitness testimony, the Washoe County district attorney's case relied heavily on testimony by the defendant's ex-girlfriend.

She testified Tavares had mishandled and abused their son before they broke up, including covering the baby's mouth and nose until he stopped breathing to prevent him from crying.

No charges were ever filed over his conduct in that relationship. But the testimony was used to help convince the jury which convicted him in the 1998 death of the three-month-old and he was sentenced to life in prison.

The high court overturned that conviction, saying the testimony was highly prejudicial and that the trial judge failed to give the jury instructions that "bad acts" evidence can only be used for very limited purposes such as supporting motives, opportunity and intent.

But the high court decided to take the issue beyond the Tavares case, expressing concern that prosecutors not use that kind of evidence to prop up a weak criminal case.

"We have often held that the use of uncharged bad act evidence to convict a defendant is heavily disfavored in our criminal justice system because the bad acts are often irrelevant and prejudicial and force the accused to defend against vague and unsubstantiated charges," said the opinion authored by Justices Miriam Shearing, Deborah Agosti and Bob Rose.

They ruled that, "the prosecutor shall henceforth have the duty to request that the jury be instructed on the limited use of prior bad act evidence." If the prosecutor fails to do so, the high court said, the district judge should do it.

And they ordered that, in future cases, the instruction should be given to jurors both at the time the evidence is presented and again when the jury begins deliberations.

Failure to do so, they said, will be strong grounds to reverse future convictions that relied on "bad acts" evidence.