Suge Knight -- Investigated for Deadly Threat at Pot Shop

Suge Knight got blazing mad at a weed shop and allegedly threatened to kill one of their employees ... TMZ has learned -- and it may all be over the marijuana payday Suge was expecting to get.

Law enforcement sources tell TMZ ... cops were summoned Sunday to an L.A. marijuana dispensary -- and when they arrived an employee dropped the dime on Suge.

We're told the store owner attempted to defuse the situation while Suge was getting angry for not getting in to the shop ... but it didn't work and that's when Suge really blew up.

According to law enforcement sources ... Suge told an employee, "I will kill you."

We're told police are now investigating Suge for felony criminal threats.

Sources close to Suge tell us this is all a misunderstanding over what he thought was going to be a promotional appearance at the dispensary ... where Suge would be paid in cash AND weed.

We're told Suge insists he didn't threaten anyone ... but did get a little heated because the shop owner refused to pay him.

Always advisable to take the high road ... when dealing with Suge.