A 15-year-old schoolboy sent pictures of male and female genitalia via WeChat to tempt a 12-year-old girl, reported Harian Metro.
The boy from Kuala Lumpur allegedly sent the lewd photographs together with a written message claiming he lusted after her.
However, the girl's mother found out about the images after inspecting her daughter's smartphone.
She sought advice from crime analyst Kamal Effendi Hashim before she was told to a lodge a police report.
The paper quoted Kamal Effendi, who lamented that such incidents are no longer rare and isolated.
"Younger people are more exposed to sexual exploitation through social media," he added.
He pointed out that two cases in Perak and Terengganu had occurred, where young girls were raped by their newfound friends whom they had befriended via WeChat.