A Texas man was executed Tuesday evening for the burning death of an elderly clerk he set on fire during a convenience store robbery more than a decade ago.

Matthew Lee Johnson was condemned for the 2012 death of 76-year-old Nancy Harris, a great-grandmother who was splashed with lighter fluid and set ablaze at a store in Garland.

Johnson, 49, received a lethal injection after 6 p.m. at the state penitentiary in Huntsville.

His was one of two executions scheduled for Tuesday in the U.S. In Indiana, Benjamin Ritchie was set to receive a lethal injection for the 2000 killing of a police officer.

These two executions are part of a group of four scheduled within about a week’s time. On May 15, Glen Rogers was executed in Florida. On Thursday, Oscar Smith is scheduled to receive a lethal injection in Tennessee.

David Dow, one of Johnson’s attorneys, said he would not be pursuing any final appeals with the U.S. Supreme Court seeking to stop the execution. Lower appeals courts had previously rejected requests by Johnson’s lawyers to stay his execution. The Texas Board of Pardons and Paroles on Friday denied Johnson’s request to commute his death sentence to a lesser penalty.

In prior appeals, Johnson’s lawyers had argued his death sentence was unconstitutional because he was improperly determined to be a future danger to society, a legal finding needed to sentence him to death. His most recent appeals had argued his execution date had been illegally scheduled.

Security video captured part of the attack against Harris.

Badly burned, she was able to describe the suspect before she died several days after the May 20, 2012, attack. Johnson’s execution is scheduled to take place 13 years to the day Harris was attacked.

Johnson’s guilt has never been in doubt. At his 2013 trial, he admitted to setting Harris on fire. He expressed remorse and called himself “the lowest scum of the earth.”

“I hurt an innocent woman. I took a human being’s life. I was the cause of that. It was not my intention to – to kill her or to hurt her, but I did,” said Johnson.

Johnson said he had not been aware of what he had done as he had been high after smoking $100 worth of crack. His attorneys told jurors that Johnson had a long history of drug addiction and had been sexually abused as a child.

In court documents, the Texas Attorney General’s Office said Johnson’s various appeals have been efforts to delay a legal death sentence.

“Thirteen years after the commission of Johnson’s crime, justice should no longer be denied,” the AG’s Office said in a court petition filed last week.

Harris had worked at the convenience store for more than 10 years, living only about a block and a half away, according to testimony from her son, Scot Harris. She had four sons, 11 grandchildren and seven great-grandchildren.