Harris County death row inmate convicted in 2006 rape-murder denied federal appeal

Dexter Johnson appears during his capitol murder trial, Tuesday, in the 208th District criminal court of the Hon. Denise Collins in the Harris County Criminal Justice Center. Tuesday, June 5, 2007, in Houston. (Steve Ueckert / Chronicle) less Dexter Johnson appears during his capitol murder trial, Tuesday, in the 208th District criminal court of the Hon. Denise Collins in the Harris County Criminal Justice Center. Tuesday, June 5, 2007, in ... more Photo: Steve Ueckert Photo: Steve Ueckert Image 1 of / 9 Caption Close Harris County death row inmate convicted in 2006 rape-murder denied federal appeal 1 / 9 Back to Gallery

A Houston death row inmate whose lawyer says he has a hole in his brain on Friday was denied a retrial, a loss in federal court that moves his case one step closer to a possible execution date.

Dexter Johnson was sent to death row in 2007 for carjacking and killing 23-year-old Maria Aparece and her boyfriend Huy Ngo after abducting them as they sat in their car on a summer night a year earlier.

Given the now-30-year-old's extensive brain damage from a severe childhood injury, attorney Patrick McCann has since argued that he shouldn't be held as morally culpable as other adults.

"If you have an actual hole in your brain that you could basically run water through at that point you have to recognize that this is a person who's not fully responsible for what they're doing," he said.

Prosecutors during his trial described Johnson as a cold and calculating killer who had "fun" when he and four of his friends took the young couple's car and drove them around town demanding money, credit cards and ATM access.

Afterward, they parked near a patch of thick woods and forced Ngo to listen as Johnson raped Aparece in the backseat.

Then, Johnson shot Ngo in the head before slaughtering Aparece. At trial, Johnson's defense team argued that it was someone else who walked the couple into the woods and fired the fatal shot.

During his trial, the then-19-year-old hurled a chair across the courtroom and at one point refused to come to his own court dates. When he heard the verdict, he covered his face and then stormed out.

Since then, Johnson's defense has filed appeals claiming earlier bad lawyering, brain damage and schizophrenia, along with alleging "a lengthy history of mental disability and psychotic breaks."

In his latest filing before the U.S. Fifth Circuit Court of Appeals, McCann asked for a new trial, raising technical arguments claiming courts didn't fully dismiss his request for one before.

Specifically, McCann said, the courts didn't decide on arguments alleging that his client lacked the brain functioning to be held to the same standard as adults. Instead, he drew parallels to past court decisions that ban executing juveniles and the intellectually disabled, saying similar reasoning should be applied to Johnson's brain damage.

But the Harris County killer lost out on the procedural argument. Now, his next chance is to take his claims to the Supreme Court.

If he loses out in the nation's highest court, there could be more appeals down the road. In light of a landmark 2017 Supreme Court decision that upended the way Texas determines intellectual disability, McCann said it's possible he could raise claims that Johnson's IQ is too low to render him eligible for execution.

In the case last year - that of another of McCann's clients, Houston-area killer Bobby Moore - the Supreme Court determined in a 5-3 ruling that Texas had been relying on a non-scientific and dated measure of intellectual disability.

The ruling set off waves of requests from inmates wanting their death sentences overturned in exchange for life behind bars, but ultimately the Texas Court of Criminal Appeals decided that even under a more modern measure, Moore didn't qualify as too intellectually disabled to face execution.