CHICAGO (CBS) — Parents in the Beverly, Morgan Park, and Mount Greenwood neighborhoods said they learned some eye-opening lessons Thursday night, when they attended a community meeting organized by police and the local alderman, in response to recent sexting incidents involving children.

Ald. Matt O’Shea (19th) said some parents appeared visibly shocked by what they heard from a Chicago police detective who specializes in online crimes.

“It was an awakening for many parents,” he said.

O’Shea organized the meeting in response to a rise in sexting among teenagers. He cited the recent case of a teen girl who took a nude picture of herself, and shared it with her boyfriend on Snapchat. He promptly shared it with friends, and since then it has continued to be shared with other students.

He was blunt in his assessment of how many parents oversee their children’s social media and other online activity.

“They need to do a better job of being parents, not their kids’ friends,” he said.

The alderman said many parents don’t have a clue their kids could get in legal trouble for sharing nude pictures of themselves.

For many parents, the digital world has passed them by. Katie O’Connor said she was amazed by the number of apps kids are using, “and how many people are using; you know, 200 million Snapchats a week.”

Chicago Police Det. Charles Hollendoner told parents about apps like Snapchat, Kick, Whisper, and others they use to communicate, and share photos or videos. He said kids won’t like it, but parents need to monitor children’s phones.

“I just want them to be able to take their kids’ phones, look at it, and if they don’t like what they see, or they don’t understand something they see, be able to communicate with their kids, and find out exactly what’s going on,” Hollendoner said.

The detective said it’s a huge responsibility these days to have a cell phone. He warned parents how predators convince young people, especially girls, to share personal information, and even inappropriate photos or videos.

“A lot of the parents were, I think, more shocked at what’s available out there,” he said.

Hollendoner said parents should get the passwords for their kids’ phones so they can monitor their activity.