Shortly before midnight last night, a mysterious fire broke out at Octavia and Oak. The blaze attracted the notice of a couple of local tipsters, who wrote in wondering about the cause of the conflagration.

According to tipster Bill B.:

Twitterer Alfredo caught a photo of the fire:

We contacted the SFFD to learn more about the incident. As it turns out, the fire was deemed an arson, but was neither a vehicle fire nor a toilet torch job, both of which types of crime have recently been reported. 

Rather, the burning item in question was found to be a shopping cart. 

According to an SFFD representative, a nearby car was also burned, but that was due to exposure to flames from the cart blaze, and not an intentional vehicle fire. 

Responding fire fighters quickly doused the blaze, but the motives behind the peculiar incident remain unresolved. 

Update, 2:20pm: The Examiner's Rob Nagle reports that while the SFFD initially believed the fire to be arson, the arson unit now says it believes the fire may have been accidental. According to SFPD Officer Albie Esparza, a homeless man told police that he was away from the area collecting materials for recycling and when he returned he saw the fire. Esparza reports that one car was completely gutted by the fire, and a second was scorched.