Boy, 15, Arrested in Poisoning of Teacher : School: Littlerock High student confesses, telling investigators that he put cleaning fluid in his instructor’s beverage can as a joke.

A 15-year-old Littlerock High School student was arrested Tuesday after he confessed to putting four to five drops of toxic cleaning fluid into his teacher’s can of Diet Pepsi, causing her to become violently ill, authorities said.

“He said he was doing it as a joke,” Los Angeles County Sheriff’s Sgt. Jerry Wolf said.

The boy, whose name was not released because of his age, was arrested about 3 p.m. on suspicion of a single felony count of poisoning or adulterating a drink, Wolf said.

Detectives identified the youth after other students said they had heard him boasting that he had placed the cleaning fluid into the soda can as a joke, Wolf said. The boy subsequently confessed to detectives during an interview, they said.

Susan Ennis, 32, an English teacher at the Antelope Valley school, was rushed to the hospital Thursday after she took a gulp from a can of soda laced with dry-eraser fluid. She was discharged from Palmdale Hospital Medical Center on Tuesday.

Ennis could not be reached for comment Tuesday.

Wolf declined to say whether the boy, who has no criminal record, showed remorse for his act. Wolf also declined to say whether any other students witnessed the incident, but he said detectives believe that the boy, who was a student in Ennis’ English class, acted alone.

“I didn’t have any doubt that we would find out who did this with as many people who must have been around,” Wolf said.

News of the arrest came as a relief to school officials who helped sheriff’s detectives interview dozens of students.

“We’re happy that finally we can bring some closure to this problem,” said Michael Clark, a vice principal at Littlerock. “I think most students were appalled at what had occurred.”

Clark said the boy, now in custody at a local juvenile detention center, will face an immediate five-day suspension and possible expulsion from the school pending an outcome of his case. The boy’s parents will meet with school officials during the suspension.

Clark said interviews with students helped school officials and detectives identify the suspect.

“It was not a surprise to us when we began to investigate because a lot of students believed a particular student or group of students had something to do with it,” Clark said. “I think the case broke when students realized it was no longer a prank and that Mrs. Ennis had suffered physically.”