RENO, Nev. -- The FBI has joined the investigation in Reno into the disappearance of a college student who police say was kidnapped from a friend's home over the weekend.

Brianna Denison, 19, was last seen around 4 a.m. Sunday when she went to sleep on her friend's couch after a night of partying.

Drops of blood were left on a pillow she used, police said, and the teddy bear her friend gave her to add support to the thin pillow is missing. Investigators added that the couch where she slept is in front of a glass door that was unlocked.

Denison, a Reno High School graduate, is a psychology student at Santa Barbara City College in Santa Barbara, Calif.

Police said she has not contacted her mother or brother -- who live in Reno -- any of her friends or her boyfriend, who lives in Oregon. Investigators said Denison may have been barefoot when she disappeared. She left behind her purse, cell phone and her clothing, which were two pairs of shoes and a skirt outfit.

Investigators are also searching for a GMC Suburban and a 45-year-old man who may be of Latin descent in connection with Denison's disappearance.

On Monday, family members pleaded for help in finding Denison and bringing her home safely. According to Fox News, Denison's family is offering $100,000 for her safe return. They have also started a Facebook page in hopes to find her.

Denison is described as 5 feet tall, 98 pounds, with long brown hair and blue eyes. Anyone with information is asked to call Reno police at 775-334-2175.