A lawyer for a Texas woman scheduled to be executed Wednesday evening filed a last-minute appeal to halt the execution, arguing that she is not mentally competent.

A woman convicted of torturing and killing a mentally impaired man she lured to Texas with the promise of marriage was put to death Wednesday evening in a rare execution of a female prisoner.

The lethal injection of Suzanne Basso, 59, made the New York native only the 14th woman executed in the U.S. since the Supreme Court in 1976 allowed capital punishment to resume. Almost 1,400 men have been put to death during that time.

Before being put to death, Basso told a warden who stood near her, "No sir," when asked to make a final statement. She appeared to be holding back tears, then smiled at two Catholic nuns watching through a window. She mouthed a brief word to them and nodded.

As the lethal dose of pentobarbital took effect, Basso, dressed in a white prison uniform, began to snore. Her deep snoring became less audible and eventually stopped.

She was pronounced dead at 6:26 p.m. CST, 11 minutes after the drug was administered.

Suzanne Basso, 59, was convicted of leading a plot to kidnap, torture and then beat to death a mentally disabled man in 1998 to collect insurance money.

The execution, the second this year in Texas, came about an hour after the Supreme Court rejected a last-day appeal from Basso's attorney who argued she was not mentally competent.

“It was a big disappointment. I would’ve expected better from the Supreme Court,” her attorney Winston Cochran told Al Jazeera shortly after the execution.

Lower federal courts and state courts also refused to halt the punishment, upholding the findings of a state judge last month that Basso had a history of fabricating stories about herself, seeking attention and manipulating psychological tests.

Cochran told Al Jazeera prior to tonight's execution that his client's trial was flawed, adding that no testimony or evidence showing that Basso personally killed Musso was presented. Nor was mitigating evidence presented at trial, including a long history of mental illness and evidence of sexual abuse as a child, he said.

"This is a very sad situation because evidence proving my client's innocence was never presented to the jury. Her attorneys at the time did not present any evidence to that effect, such as her mental health issues and a history of child abuse." Basso has been diagnosed with six different mental health issues, according to Cochran.

Cochran also questioned the testimony provided by Dr. Paul Shrode, the state's medical examiner.

"Basso was nowhere near the guy when he was actually killed," Cochran told Al Jazeera.

Basso, who was paralyzed and bedridden, suffered from a degenerative disease. Her lawyer had aired concern prior to the execution over the effect that the lethal drug injection may have on his client, who is currently on medication. "With her medical condition, only God knows what this is going to do to her body. She's one of the sickest people to be put to death. She's been flat on her back for years," he said.

A Guardian investigation last week found that Texas executions now take on average twice as long as they did before the summer of 2012, when supply shortages forced the state to switch to the anesthetic pentobarbital.

Before that, Texas executions generally lasted between 9-11 minutes. Currently, the duration varies widely, from a minimum of 12 minutes to a maximum of 30. Ten of the 27 executions since the switch to pentobarbital have taken at least 25 minutes.

Texas is the latest of a half dozen U.S. states turning to state-regulated compounding pharmacies to obtain controversial execution drugs after overseas companies refused to supply drugs for executions on ethical grounds.

Compounding pharmacies typically mix drugs for individual prescriptions and are subject to light government regulation, required to register with state authorities but not regulated by the Food and Drug Administration.

The practice has drawn protests from opponents of the death penalty and advocates for death row inmates, who say the lack of regulation risks a botched execution.

A Massachusetts compounding pharmacy was the source of tainted pain injections which caused an outbreak of a rare type of meningitis last year that killed at least 50 people and sickened hundreds in 20 states.

Wednesday's execution marked the seventh of the year in the United States, according to the Death Penalty Information Center, a monitoring agency.

Al Jazeera and wire services

Texas, which executes more people than any other state in the U.S., executed Basso by lethal injection at its death chamber in Huntsville.