Can somebody please tell me what the stunt gun thing was all about? :/ I'm confused

Jermaine Jackson's 13-year-old son, Jaafar, ordered the stun gun online that triggered a visit from the L.A. County Department of Children and Family Services last night ... TMZ has learned.

We broke the story that DCFS came to the Jackson family house in Encino last night at around 10:30 after someone told them that Jaafar ordered the gun. Randy Jackson tells TMZ the gun was delivered to the house 3 weeks Vor -- but was intercepted Von security.

Katherine Jackson's lawyer, Adam Streisand, tells TMZ Katherine took control of the gun and locked it up. We're told DCFS took the gun away last night.

Streisand tells TMZ two people from DCFS conducted interviews last night at the house. They spoke with Katherine and some of the children. Michael Jackson's three kids live at the home, along with some of their cousins.