Sean Kingston: I've Been Kidnapped Over Jewelry ... Cops Investigating

Sean Kingston claims he was kidnapped by a jeweler in a dispute over a $225,000 watch ... and LAPD is now on the case.

Here's what Sean says ... he bought the watch from a jeweler and made payments to the tune of $185k, but didn't pay the balance because he felt the watch wasn't worth any more. The jeweler begged to differ and they had a number of arguments.

Sean told cops he and the jeweler met Tuesday at 1:50 AM at a downtown L.A. parking lot, to make a trade ... he'd give the watch back and the jeweler would give him a watch worth a solid $185k. Yes, it sounds weird.

Sean says he got in the back of the jeweler's car but instead of trading, the jeweler allegedly snatched Sean's watch away and refused to give him another watch. Sean says he went nuts, demanded the watch back and refused to get out of the car.

Now for the jack move. Sean says the jeweler and his posse locked him in the car and drove away to a secluded area and threw him out of the car. Cops say if true, it's kidnapping.

We know it's a little confusing. Here's a road map ...