Police have found the missing truck of a man wanted for questioning in the disappearance of a 19-year-old college student, but the teen remains missing, a sheriff's spokesman said Friday.

Convicted sex offender John Steven Burgess, 35, was arrested late Tuesday in Jacksonville, Fla., after police spotted him trying to dispose of a bag of crack cocaine outside a Motel 6, said Jim Amormino, spokesman for the Orange County sheriff's department. Donna Jou was last seen June 23.

Amormino said extensive media coverage of Burgess' arrest led an anonymous tipster to call police with the location of the man's 1998 blue Ford Ranger truck. Amormino would only say that the truck was found in the Jacksonville area and was being processed by forensic investigators Friday.

Amormino said homicide investigators from Orange County were in Florida, where Burgess is currently being held on a drug charge and a California warrant for failing to register as a sex offender.

Burgess has not been charged in connection with Jou's disappearance, but authorities remain suspicious, he said. His Torrance-based attorney, George Bird Jr., did not immediately return a call Friday.

Jou, a biology student at San Diego State University, lives with her mother in Rancho Santa Margarita. She was last seen heading to a party at Burgess' rented house in West Los Angeles.

Her mother received a text-message the next day that said her cell phone battery was dying, but she'd be home soon. She has not been heard from since.

Amormino said two weeks after the teen disappeared, residents found a black plastic tool box in the street 1 1/2 miles from Burgess' house. The box contained a license plate, a pair of gloves, rope and a scrub brush. The license plate read SINJIN1, which Amormino said represented Burgess' alias, Sinjin Stevens.

Investigators also found a motorcycle helmet in the box. Jou was last seen hopping on the back of Burgess' motorcycle wearing a helmet he had supplied her.

Sheriff's investigators have also said authorities received an e-mail message from Burgess, which offered his "attempt to communicate his thoughts and his feelings of essentially what may have occurred."

Amormino said authorities are not currently releasing the contents of the e-mail.

The girl's mother, 48-year-old Nili Jou, said she's confident her daughter is alive and well.

"It's not over yet," she said. "Donna is going to be back. I believe in God and I believe that God won't let any harm come to my daughter."

Investigators initially sought two men as persons of interest. They now believe Burgess used the photo of another man while contacting Jou online. Burgess was convicted of three counts of battery in 2002 and of performing a lewd act against a child the following year.

Burgess is being held on $1 million bond, but it will be at least two weeks before he is extradited to California, authorities said.