Antioch police made a gruesome discovery Wednesday afternoon when they were performing a welfare check at a home near the DeltaFair Shopping Center.

Police were called to a townhome at 2600 Fairmont Lane and arrived just after 4 pm, as Bay City News reports. Inside the home, they found the bodies of a 39-year-old man and a 65-year-old woman "in advanced stages of decomposition," but police provided no further details about the nature of their injuries or where the bodies were found.

46-year-old Mark Taylor was at the home and attempting to leave, and police arrested him on suspicion of murder. Investigators believe that Taylor killed both victims, who were his half-brother and his mother.

As KTVU reports, Taylor has not yet been charged, but he faces two counts of murder. It is unclear how long the bodies may have been inside the home after the killings.

The townhome where the murders took place is part of a group of similar, two-story, attached homes with covered carports, a short distance from the DeltaFair Shopping Center and just a couple of blocks from Highway 4.

No motive for the killings has been discussed.

Anyone with information about this case is asked to call Antioch Police Detective Adam Duffy at 925-779-6884 or reach him by email at [email protected].

Photo via Google Street View