Ramiro Hernandez-Llana, a 44-year-old Mexican was executed in Texas Wednesday for fatally beating a former Baylor University history professor in 1997.

Hernandez-Llanas was an illegal resident at the time of his arrest in October 1997 for killing 49-year-old Glen Lich. Investigators said that Hernandez-Llanas repeatedly beat Lich with a piece of steel rebar and then attacked Lich's wife. She survived and testified against Hernandez-Llanas.

Tied to a hospital gurney inside state's death chamber in Huntsville, Hernandez-Llanas begged for mercy. Speaking in Spanish, Hernandez-Llanas said, "I'm looking at the angel of God. I ask forgiveness from the family of my boss."He also urged his children to "take advantage of your time on earth," NY Daily News reports.

Hernandez-Llanas was just the second Texas prisoner to be given a lethal injection of pentobarbital. He was pronounced dead at 6:28 p.m. Hernandez-Llanas was also the sixth inmate executed this year in Texas.

Texas Department of Criminal Justice officials did not disclose the source of the powerful sedative so as to shield the drug's supplier from threats of violence from opponents of capital punishment. Texas and other states that offer death penalty have been demanding new drugs after key drugmakers, who oppose death penalty, stopped businesses with prisons and corrections departments.

In 2004, the International Court of Justice in The Hague, Netherlands, ruled that four dozen Mexican citizens, who were on execution orders in the U.S., did not receive full consular rights at the time of their arrests. The U.S. Supreme Court's order to implement the ruling has not been well-received in Congress.

Euclides del Moral, a Mexico Foreign Ministry deputy director general, said that there were "certain gray aspects" in the consulate notification in Hernandez-Llanas' case. The execution of a Mexican national is of great concern."

Hernandez-Llanas arrived in Texas after fleeing from a Mexican prison, where he was serving a 25-year sentence for a 1989 murder in Nuevo Laredo, rape of a 15-year-old girl and a stabbing in Kerrville. He was discovered with homemade weapons in prison and is reported to have slit an inmate's face with a razor blade.

"This is exactly why we have the death penalty," Lucy Wilke, an assistant Kerr County district attorney and Hernandez-Llanas's prosecutor, said. "Nobody, even prison guards, is safe from him."