NEW YORK (CNN) -- On May 4, 2007, Kara Kopetsky, a 17-year-old high school junior in Belton, Missouri, was not having a good day.
Kara Kopetsky, 17, left school early in Belton, Missouri, on May 4, 2007, and hasn't been seen since.
She forgot one of her textbooks and called home and asked her mom to drop it off at the school office. She also asked her mother to wash her uniform so she could work the 4 p.m. shift at Popeye's Chicken.
Later that morning, Kara had an argument with one of her teachers in class, according to police and her family. Frustrated, she left campus about 10:30 a.m., ditching school for the rest of the day.
A school surveillance video shows her walking out. But no one can say which way she went, or whether she got into a car.
It was the last time anyone saw or heard from her.
Police say there has been no activity on Kara's cell phone since shortly after she walked out of school. They followed some pings from the phone, conducted some searches, but found nothing significant. Beyond that, they aren't commenting. Watch an update on the case »
Kara's stepfather says the cell phone's long silence makes him suspicious.
"This doesn't make any sense," said Jim Beckford. "Kara was on her cell phone sending texts constantly. Her cell phone bill was typically 80-100 pages long."
When Kara didn't come home from school as usual, her family -- mother Rhonda, stepfather Jim and stepbrother Thomas -- grew worried. They filed a missing persons report later that afternoon.
Police told them they believed Kara was a runaway, and that she'd come back on her own in a few days.
Two years later, her family hasn't heard a word from Kara. She left behind most of her belongings -- money, clothes, iPod and a new carton of cigarettes. Her bank debit card was left in her school locker and her bank account, with $150 from her recent paycheck, remains untouched.
According to police in Belton, the case is being actively investigated. But with no certain evidence of foul play, police continue to characterize Kara's disappearance as an endangered and missing adult case.
The state of Missouri considers Kara Kopetsky to be an adult because she was 17 when she disappeared.
Belton Police Capt. Don Spears said police are looking at several persons of interest, but haven't narrowed their investigation to focus on a single suspect.
Her family says she has no history of running away. They say they fear that she was abducted when she left school that day.
"She is a very beautiful girl and so we often warned her to be careful, but like any teen, she had an attitude that she was invincible," her stepfather said.
About a month after she disappeared, Kara's case was eclipsed by another sensational case -- the abduction and slaying of Kelsey Smith.
Smith was taken from a store parking lot in Overland Park, Kansas, and her body was found in the Missouri woods, six miles from Kara's home in Belton. A suspect was charged, pleaded guilty, and is serving a life sentence.
Police in Belton and Overland Park compared notes but could find no connection.
According to family and police and Kara's MySpace profile, she had an on-again, off-again boyfriend. He lived in her neighborhood, was 18, and attended the same high school but dropped out earlier the spring Kara disappeared.
Kara was trying to end the relationship, friends told police. It is unclear whether the two saw each other the day Kara vanished.
A $30,000 reward is offered for tips leading to the whereabouts of Kara Kopetsky or the arrest of anyone responsible for her disappearance.
Police and family urge people to call the Belton Police Department's tip-line at 816-474-TIPS. Kara is described as 5 feet 5 inches tall and 125 pounds with brown hair and hazel eyes.