An undercover police officer tricked a teenager with autism into buying pot for him, a lawsuit filed by the boy's parents alleges.

The 17-year-old, who isn't named in the lawsuit, was arrested with 21 other high school students on drug-dealing charges as part of a sting operation last December at Chaparral High School in Temecula, Calif., and neighboring schools. His parents, Catherine and Doug Snodgrass, on Wednesday announced a lawsuit in state Superior Court that seeks unspecified damages from the Temecula Valley School District, alleging negligence and intentional infliction of emotional distress.

"Certain parts of my son have been damaged in ways that I think will be permanent," Doug Snodgrass told The Huffington Post.

According to the Snodgrasses, a police officer pretended to be their son's friend, which pleased them because he has trouble making friends. When the couple suggested inviting this new friend home, the friend "would always have an excuse, saying he couldn't or he was grounded," Catherine Snodgrass said. The parents said they later learned the "friend" was Deputy Daniel Zipperstein of the Riverside County Sheriffs Department, who was posing as a student named Daniel Briggs for several months at their son's school.

Zipperstein hounded their son to sell him marijuana or his prescription medication, the parents said they later learned.

The teen couldn't access his prescription medication because his parents keep it locked. After more than three weeks of pestering, the teen bought a half-joint from a homeless man and gave it to the officer, who had given him $20 weeks earlier, according to the Snodgrasses. The teen did this once more before refusing to continue, prompting the deputy to end the supposed friendship, the parents said.

The couple said their son was arrested soon after that. He was taken to the police station and was not allowed to see his parents until his court date two days later, the parents said.

Once they were able to see him, Catherine Snodgrass said in the below video, taken at a community meeting the parents helped organize in August, she found her son traumatized. "The look in his eyes will forever haunt us," she said. The parents have started a legal fund to help pay for the lawsuit.

Since his arrest, the teen has been suffering from post-traumatic stress disorder, which has included insomnia, panic attacks, depression, paranoia and infliction of self-injury, his parents said. Before the arrest, in addition to autism, their son had been diagnosed with bipolar disorder, Tourette syndrome and anxiety disorders.

The drug sting resulted in the arrests of 15 students from Temecula Valley High School, five from Chaparral High School and two from Rancho Vista Continuation High School. Authorities seized heroin, LSD, ecstasy, marijuana, cocaine, methamphetamines and illegal prescription drugs.

Critics of undercover drug stings argue it's unfair to target teenagers, who are often emotionally vulnerable. Sending police and informants to entrap high school students is sick, Tony Newman, director of media relations at the Drug Policy Alliance, said in a statement. We see cops seducing 18-year-olds to fall in love with them or befriending lonely kids and then tricking them into getting them small amounts of marijuana so they can stick them with felonies.

The Riverside County Sheriffs Department declined to speak with HuffPost, but said in a statement that the department "followed all pertinent laws and the case was reviewed by the DA's Office. Had there been entrapment issues, the DA's Office would not have filed the case."

Temecula Valley School District said in a statement to HuffPost that it did not initiate the investigation, but cooperated when approached by the sheriff's department. Chaparrel High School declined to comment.

A 2007 Department of Justice report found that drug stings can have favorable results in the short term, but can force dealers underground and have not demonstrated long-term success.

Drug stings have become an annual occurrence in Riverside County, which includes Temecula. In 2011, deputies posing as students spent four months at high schools in Moreno Valley and Wildomar, arresting 24 students on drug-dealing charges. In 2010, 14 students were arrested in an undercover sting at Palm Desert High School.

Diane Goldstein of Law Enforcement Against Prohibition, a coalition of former police officers dedicated to opposing drug war policies, told HuffPost she met the Snodgrass' son.

"Within two minutes, you can tell this kid does not have the capacity to understand what he's doing," Goldstein said. "It's abhorrent that an undercover officer would continue to try to get him to sell drugs.

"What's our obligation to our kids? We should develop holistic programs to make children successful rather than merely punishing them," Goldstein, a retired lieutenant commander of the Redondo Beach Police Department, added. "Otherwise its a school-to-prison pipeline."