Four days after she disappeared, Reno police still have no new leads concerning 19 year-old Santa Barbara City College student Brianna Denison.

Reno police, with the help of the FBI and numerous other law enforcement agencies, are currently searching for any clues into what authorities have called the probable kidnapping of the 19 year-old college student. Denison was last seen at approximately 4 a.m. Sunday morning. Police and K-9 units canvassed the neighborhood surrounding the Mackay Court residence, where Denison was last seen, interviewing residents and handing out fliers with Denison’s photo.

The Regional Sex Offender Unit is in the process of interviewing the nearly 100 registered sex offenders reported living within a mile of the Mackay Court residence. In addition, the RSOU will contact the over 1,700 registered sex offenders in Washoe County, where the city of Reno is located.

The man driving a beige SUV who was wanted by police for questioning came forward Tuesday after hearing news reports of the investigation. According to Reno police, the man, who provided a ride to the Mackay Court residence for a friend of Denison’s, had no involvement in Denison’s disappearance and is no longer a person of interest.

Investigators are still awaiting test results from the pillow Denison had slept on the night preceding her disappearance. Police believe the pillow had traces of blood on it.

Denison, a psychology student at SBCC, is a resident of Reno, Nevada, and was spending her winter vacation at home with her family. On the night of her disappearance, Denison was staying the night with a friend who lived near the University of Nevada, Reno. According to authorities, neither Denison nor her friend had heavily consumed alcohol on the night in question.

The following morning, Denison was gone. Her personal belongings, including a cell phone, purse, clothing and two pairs of shoes, were left undisturbed.

While police have yet to determine any clear connection, authorities are not ruling out the possibility that the disappearance is related to two earlier assaults on female college students near the UNR campus late last year. Investigations into these incidents are ongoing at the moment.

Law enforcement agencies are continuing to ask anyone with information to call the 24-hour tip line at (775) 745-3521.