MIAMI -

A man charged in a fatal hit-and-run was taken back to jail after he failed a drug test.

Police say Sandor Guillen, 38, was drunk when he drove his sport utility vehicle down a Busway lane at 100 mph, T-boning a van carrying 13-year-old Kaely Camacho, her father and her older sister, and then ran away from the scene.

Camacho was killed in the crash.

Guillen failed a random drug test Friday when he tested positive for amphetamines, which he said were prescribed to him. He told Miami-Dade Circuit Court Judge Ellen Sue Venzer he takes Adderall for attention deficit disorder.

"You see a doctor who prescribed a controlled substance to you and you don't know that person's name?" said Venzer. "You only know them by their initials. I personally call him 'doctor.' I know they call him DK in the office. I don't know what the DK stands for."

"Unfortunately, ma'am, right now, I can't remember," answered Guillen.

Well, then why don't you sit down and start thinking," said Venzer. "This is what I'm going to do, I'm going to take him into custody."

The judge ruled Guillen be held in jail until Monday when Bruce Lehr, his attorney, said he'll show the drugs were prescribed. Lehr added the prescriptions were okayed by Guillen's community control officer.

"All I have is a gentlemen who is charged with a serious crime, who has tested positive for amphetamines, who's just telling me that he has a prescription, but could not describe to me who the doctor was, why he goes to Fort Lauderdale to a nurse practitioner when he lives down south," said Venzer, "I can't get anybody on the phone and you're not giving me a prescription a letter or anything else."

Guillen has been under house arrest since pleading not guilty to four felony counts, including vehicular homicide and DUI manslaughter, in May 2012. He was released on bond.