"I don't know what more we can do to stop something like this from happening," said Barbara Wyatt, a school district spokeswoman. "We don't want any improper relationship, but how much can you do to avoid it?"
Pena is a precocious teen who will raise his hand to answer a teacher's question--provided he is sure he knows the answer, friends said with a laugh--as he did while reading "Antigone" in a recent English class.
He is enrolled in a program called AVID, or Advanced Via Individual Determination, a type of college preparatory program, said classmate Danielle Holleman, 15, a sophomore.
Hadden was quite popular among students. Several recalled Thursday that they enjoyed going to some of her science classes. The classes were filled with educational games and exercises designed to introduce classmates to each other--a necessary step in a school with an estimated 3,000 students.
Many students went to her classroom after school just to do homework and hang out because it was more fun than going home, others said.
"Most teachers kind of treat you like a robot," Holleman said. "She wasn't like that. Some students do get close to teachers. If you have problems at home, they can be someone to talk to. She was a good person to talk to."
Knowledge of a close relationship between Hadden and Pena appears to have been common knowledge, many students said Thursday. Not only were there widespread allegations about an intimate relationship, but Hadden often drove Pena and his friends home after school.
"You know how kids are," said 15-year-old Dale Caddell, a sophomore, while pointing out that he will turn 16 in a matter of days. "They feel like it's no big deal, and there is no use in getting in trouble just because you suspect something. Next thing you know, some kid disappears."
Other students remained more surprised by the allegations.
"Not Miss Hadden!" said Jason Cruze, 16, a 10th-grader, upon learning that the pair had been caught together in a Las Vegas hotel room. "She was cool!"