A Mexican Mafia hit man convicted of beating and strangling a San Antonio woman because she didn't pay the gang's 10 percent tax on her illegal drug sales was executed Wednesday evening.

The injection of Manuel Vasquez with a lethal dose of pentobarbital leaves Texas with enough of the powerful sedative to carry out only one more execution. Vasquez was the fourth Texas inmate put to death this year, and at least six are scheduled for execution in the coming weeks.

Texas prison officials, like those in other death penalty states, have found it increasingly difficult to find suppliers to provide drugs intended for capital punishment use.

Vasquez, 46, was pronounced dead at 6:32 p.m. CDT, 17 minutes after the drug began being administered.

Vasquez, in a final statement, told his family and friends he loved them and thanked "the Lord for his kind mercy, faithfulness and unconditional love."

"In Jesus' name I pray," he said, then told the warden: "I'm ready."

He took three deep breaths, then began snoring loudly. The snores became progressively quiet, and all movement stopped within less than a minute.

The sister of his victim was among witnesses watching through a window. He never looked at her. His own sister and a female friend cried as they watched in an adjacent room.

Vasquez's lawyers filed no late appeals to delay his execution for the 1998 slaying of 51-year-old Juanita Ybarra.

Testimony at Vasquez's trial showed Ybarra had ignored the gang's "dime" tax on street drug sales in San Antonio, so Vasquez and two partners were ordered that she "had to go down."

"I'm sure she was told if you're selling, you've got to pay the tax," said Mary Green, an assistant Bexar County district attorney who prosecuted Vasquez.

"I guess she didn't take it seriously."

Fueled by a night of drinking and drugs, the men put on bandannas to cover their faces and socks on their hands to prevent fingerprints and barged into a room at a run-down San Antonio motel where Ybarra was staying with her boyfriend, Moses Bazan.

Bazan was beaten and stabbed but survived to identify one of the attackers, leading to the arrest of all three. He said he saw Vasquez ask one of his companions for a phone cord and saw Vasquez strangling Ybarra.

One of the men, Johnny Joe Cruz, testified against Vasquez under a plea deal that carried a seven-year prison term. The third man charged, Oligario Lujan, is serving a 35-year sentence.

Court records show the three were carrying out orders from Mexican Mafia boss Rene Munoz, who spent years on the Texas Department of Public Safety's 10 Most Wanted List until his arrest in 2012.

Vasquez had a lengthy record and had been in and out of prison at least twice. One conviction involved the beating of a man who died after his body was set on fire, and he was tied to the 1992 slaying of another drug dealer who wasn't paying the gang's drug tax.

Texas' next execution is scheduled for next week. Randall Mays is set to die for a 2007 shootout where two East Texas sheriff's deputies were killed.

Executions set for April in the nation's most active death penalty state will require a new lethal drug supply to be carried out.

Some states have started considering other options. Utah's Legislature gave final approval Tuesday night to a proposal to allow executions by firing squad if there is a drug shortage. Legislation to allow firing squads also has been introduced in Arkansas, while a Wyoming firing-squad measure failed. In Oklahoma, lawmakers are considering legislation that would allow the state to use nitrogen gas to execute inmates.

"I remain optimistic we'll be able to carry out executions according to the schedule," Brad Livingston, executive director of the Texas Department of Criminal Justice, has told The Associated Press. "Time will tell."