By Karen Brooks
AUSTIN, Texas (Reuters) - A man convicted of killing his girlfriend's sister and a Texas Tech University associate dean was executed by lethal injection on Thursday, the second execution this week in Texas.
Vaughn Ross, 41, was pronounced dead at 6:38 p.m. CDT (2338 GMT) at a state prison in Huntsville, Texas, the state Department of Criminal Justice said in a statement.
The victims, Douglas Birdsall and Viola McVade, were found shot to death in January 2001 in Birdsall's car in a ravine in Lubbock, Texas, according to an account of the case from the state attorney general's office.
Birdsall, 53, and McVade, 18, both had been shot several times, the account said. McVade was the sister of Ross's girlfriend, and Birdsall was an associate dean of libraries at Texas Tech University in Lubbock.
Ross, who held a college degree from a Missouri university and was putting himself through architecture classes at Texas Tech, was convicted and sentenced to death in September 2002.
He pleaded not guilty to the charges, with his lawyers arguing he could not have committed the crime alone and that police had planted evidence.
Ross told prosecutors he had been fighting with McVade and had threatened her the night before her body was found, according to the attorney general's account.
After Ross gave police permission to search his house, investigators found a bloodstained sweatshirt with DNA from both Ross and Birdsall.
Inside Birdsall's car, a latex glove carried DNA that matched both men, and a large pool of blood in the alley behind Ross' apartment matched Birdsall's DNA. The car and bodies were found about four miles from Ross's home.
After his arrest, while he was in jail, Ross told his mother he "might have" committed the crime, the account said.
Ross, in a final statement, thanked his family and friends for their support and said he did not fear death, the department said in a statement.
"We know the lies they told in court," Ross was quoted as saying. "We know it's not true. I want you to be strong and keep going."
Ross was the 10th inmate executed in Texas and the 20th in the United States this year, according to the Death Penalty Information Center.
On Tuesday, Texas executed John Manuel Quintanilla Jr for the murder of a man during a robbery at a game room.
(Additional reporting by David Bailey; Editing by Greg McCune and Ken Wills)