LIVINGSTON — A toxicologist whom state prosecutors fought to put on the stand during a high-profile Livingston Parish rape case retrial described for jurors the different levels of alcohol intoxication Tuesday but wasn't allowed to weigh in on whether a woman videotaped during a 2014 sexual encounter was aware of what was going on. 

Melanie Curtin is accused of simple rape and video voyeurism. Prosecutors say she and former Livingston Parish deputy Dennis Perkins violated an incapacitated woman in November 2014.

The woman told jurors last week that she was too intoxicated to remember the incident, and the state wanted Dr. Patricia Williams to address the level of consciousness the woman may or may not have had. After the defense objected, the 1st Circuit Court of Appeals and the state Supreme Court said Williams could speak only generically about intoxication.

Williams had worked on a Max Gruver hazing case at LSU, in which the student died, and helped write a bill regarding drug and alcohol testing. She has taught toxicology and has served as an expert witness in previous trials.

Williams said people "have different levels of cognition as alcohol takes over" and that a person can be in an alcoholic stupor and maintain a residual awareness.

"You only have awareness of stimuli, but maybe cannot react," Williams said.

Previously, prosecutors said it appeared the woman captured on videotape was incapacitated and unable to give consent.

Williams said the difference between a stupor and a blackout is that a person who is blacked out may appear alert. A person in an alcoholic stupor is not.

Describing sex during a stupor, Williams said, “There’s a stimulus, that’s all you know.” She said such a person would be defenseless, though still able to move. 

The victim testified last week that she had so much to drink she wasn't aware of who initiated sexual activity among her, Curtin and Perkins, the former deputy at the center of a yearslong sex-crimes investigation.

After Williams' testimony Tuesday, jurors reviewed photographs, videotapes and text messages between the woman on the tape and Curtin.

The trial is scheduled to resume after lunch.

According to the state, Curtin took part in a videotaped assault with Perkins, who is serving a 100-year prison term for sex crimes involving minors. The charges against Curtin have nothing to do with juveniles.

Perkins and his wife Cynthia were arrested in October 2019 and ultimately faced 150 counts alleging they raped two children and an adult, produced child pornography and served schoolchildren baked goods contaminated with a bodily fluid. Perkins is serving 100 years in prison after pleading guilty to a number of charges, and Cynthia Perkins was sentenced to 41 years.

Curtin was previously convicted and sentenced to life in prison, but the 1st Circuit said the trial judge erred when he admitted some evidence harmful to Curtin and rejected other items that could have benefited her case.