The woman arrested Wednesday with Mr. Irvin on misdemeanor marijuana charges, 21-year-old Nelly Adham, is the fugitive's sister.
The FBI anti-drug task force that made the unplanned arrests Wednesday night was after Ronda Adham, whose name has appeared in some official records as Rhonda Adaham. She was one of 17 suspects arrested in May and accused of participating in a heroin and cocaine ring that supplied fatal doses to Mr. Tuinei and two 18-year-olds in Carrollton and Allen last year, according to a May federal indictment.
FBI Special Agent Lori Bailey said officers of the task force, which is continuing investigations begun after the three deaths, happened on the pair while trying to arrest Ronda Adham, 20, for violating the conditions of her release on bond. It remained unclear Thursday how Ms. Adham violated her bond, and Agent Bailey declined to say.
It also remained unclear how Mr. Irvin came to know Nelly Adham. Neighbors in the Far North Dallas apartment complex where the pair were arrested, and where authorities hoped to find Ronda Adham, said Mr. Irvin was often seen visiting in his Mercedes. Complex officials would not say who was renting the apartment; Agent Bailey said she did not know.
After his release from the Plano jail Wednesday night, Mr. Irvin, 34, denied wrongdoing and said he did not know Ronda Adham. He could not be reached for comment Thursday.
Relatives of the sisters declined to comment.
"I'm not going to get involved in this," said their father, Dr. Abdallah Adham, a Dallas internist. "My daughter is an adult, and she can help herself."
When authorities knocked on the apartment door looking for Ronda Adham on Wednesday, Nelly Adham and Mr. Irvin would not respond, Agent Bailey said. Then agents broke down the door and found the pair with a small amount of marijuana, she said.
Officer Carl Duke, a Plano police spokesman, said that Mr. Irvin was naked and that the drug was found in his possessions.
Before the arrest, Agent Bailey said, police officers discovered Mr. Irvin's car while checking license plates at the complex. But task force officers did not know he was in the apartment they were about to target, she said.
On Thursday night, WFAA-TV (Channel 8) reported neighbor Shannon Davis' assertion that the officers called out only Mr. Irvin's name at the door of the apartment, even though the warrant was for Ronda Adham.
Agent Bailey called the report untrue.
"The only name that was spoken by task force personnel was that of Ronda Adham," she said. "They called for Ronda Adham to open the door several times, and our request was not complied with."
No cocaine charges have been filed against Mr. Irvin, despite earlier reports that a trace amount of a substance appearing to be cocaine was found. He recently finished serving four years of probation for possession of that narcotic.
Dallas County state District Judge Manny Alvarez, who sentenced Mr. Irvin in that case, told KTCK-AM (1310) Thursday morning that he was surprised Mr. Irvin completed the probation successfully. "I really had my questions to whether he would comply," the judge said.
Barbara Goodman, who is a longtime family friend of the Adham sisters' and is their father's office manager, said the women had been estranged from their parents because of previous legal troubles. The FBI called Dr. Adham's office Wednesday looking for Ronda but no one knew where she was, Ms. Goodman said.
"It's been like an ongoing thing, their problems," said Ms. Goodman, who has worked for their father 21 years and once baby-sat the sisters. "Their peers and the world can mess people up."
Ms. Goodman said the doctor has not taken the publicity well. "It's completely floored him," she said.
Nelly and Ronda Adham have a history of arrests for check theft, forgery and traffic violations dating to 1996, Dallas County records show. Nelly Adham apparently was never linked to the alleged drug-trafficking organization that federal authorities said they broke up after Mr. Tuinei's death.
The May 2000 federal indictment that outlines the charges and evidence against 17 alleged ring members said Ronda Adham sold drugs to pay for her own habit. Investigators secretly recorded her begging an alleged ranking member of the organization, Jesus Carbajal, for "a quarter and some white" because she had just been released from a rehabilitation center.
At one point, Ronda Adham was recorded telling Mr. Carbajal that "she was sick and wanted his drugs," the indictment states.
Nelly Adham has been in trouble as recently as last week, when she was arrested on a charge of forging a check. She was released from the Lew Sterrett Justice Center on Aug. 3.