CASTLE ROCK, Colo.—A man accused of dragging his girlfriend to death behind a car may have scored low on an IQ test because he had trouble assimilating into U.S. society, and not because he is mentally retarded, a prosecution witness testified Tuesday.
Jose Luis Rubi-Nava, 37, is charged with murder and kidnapping and could face the death penalty unless a judge rules he is retarded, as the defense maintains.
The mangled body of his 49-year-old girlfriend, Luz Maria Franco Fierros, was found in September 2006 near Castle Rock just south of Denver. She had a nylon strap around her neck and her body lay at the end of a 1 1/2-mile trail of blood.
The coroner said she died from strangulation and massive head wounds.
Authorities have said both Rubi-Nava and Franco Fierros were from Mexico and may have been in the country illegally.
The defense has argued that an IQ test given to Rubi-Nava showed he was mentally retarded. The test was administered by a defense expert and the specific results have not been made public.
The test was a version of the Wechsler Adult Intelligence Test developed in the U.S. and translated for use in Mexico.
Psychologist Enrique Suarez of Coral Gables, Fla., called to testified Tuesday by prosecutors, said Rubi-Nava’s test results were improperly compared with random samples from the United States.
Suarez said Rubi-Nava’s results should have been compared with random samples from Mexico. Even though Rubi-Nava, a landscaper, had lived in the United States for several years, he likely did not learn enough of the culture to be compared with a U.S. sample, Suarez said.
Authorities have not said how long he had been in the United States.
“They (Spanish-speakers) don’t assimilate the way other immigrant populations assimilated,” said Suarez, who was born in Costa Rica and grew up speaking Spanish. “It’s very much delayed because you have larger communities.”
In Miami, he said, some stores jokingly display signs saying “English is spoken here” because English is a rarity compared with Spanish.
He said differences in language and culture, and the phrasing of the test itself, play a large role in an individual’s results.
Someone from Mexico would score higher on the test if their results were compared with others from Mexico than with someone from the United States, he said.
“You could take that to the absurdity of taking anybody from this room, testing them in China and finding that they’re mentally retarded based on the criteria of that population,” he said. “They should be compared with the population from which they are drawn from.”
The defense expert who administered the test, Ricardo Weinstein, has defended his findings.
“The question I’ve been asked to answer is, how does he compare cognitively to the population of the United States?” Weinstein said at an earlier hearing. “And I have to use the norms for the United States.”
At a hearing in January, a state mental health doctor testified that Rubi-Nava is not mentally retarded and has decent communication skills, follows instructions and can do simple math problems.
