A planned exchange in the Outer Sunset on Friday afternoon turned into a armed carjacking when the deal went sour.

The incident took place near 42nd Avenue and Ulloa Street around 4 p.m. when two 19-year-old males met the suspect, a 40-year-old man, for what police described as a "transaction" that "failed."

After the situation escalated, the suspect took out a gun and got into a victim's vehicle before driving a short distance away. The car was recovered, but the suspect stole their car key and cell phones. Police noted that the stolen items weren't related to the transaction which initially brought the parties together.

Anyone who has information about this incident is encouraged to contact SFPD via the department's anonymous tip line at 415-575-4444, or text TIP411 with "SFPD" at the start of the message.

Here’s why we usually don’t include suspect descriptions in crime reports.