A neighborhood resident who lives on the 1300 block of McAllister Street found an unpleasant surprise when gardening last month: human remains.

The bones were discovered not in a private back yard, but in a planter box in front of the house. KTVU reports that a mandible (a piece of the jawbone) may have been discovered in the soil. 

The Chronicle reports that the bones were dropped off at Northern Station on November 23rd, spurring an investigation into their origin. The Medical Examiner's Office later determined that they were human.

Cadaver dogs were brought onto the scene, and while initially it was believed that there were more remains to be found, an excavation conducted by the Medical Examiner and Chico State turned up nothing more. SFPD spokesman Officer Carlos Manfredi said that they are currently working to determine the age, sex, and the amount of time the bone may have been buried, as well as comparing it to logs of missing children and adults.

This isn't the first time that mysterious bones have turned up in the area. In 2013, bones were uncovered behind a house on Masonic near Page Street. The discovery came with a rush of media attention, as their location was a mere block away from where Kevin Collins, a boy who disappeared in 1984, was last seen. The remains were later determined to be from an animal.