SAN FRANCISCO (CBS SF) — One multi-million dollar home on an unstable San Francisco hillside was already being torn down Friday and now additional homes are at risk.

As homeowners on Casitas Avenue watch Ronald Martell’s home being demolished, many were wondering if their house could be next.

Martell was watching along with his neighbors on Friday as crews worked to dismantle his dream home after it slid 14 inches.

“There’s concern amongst everybody in the neighborhood that this whole hillside could be in danger,” said Martell.

When asked what the worse-case scenario was for homes on the hillside, Granite Drilling and Shoring owner Joe Cassidy replied, “Well, the worst case scenario could be you know a couple of other houses may get demolished here if this hill here doesn’t stop moving.”

On Friday, workers discovered the earth under the home next to Ronald’s property moved a couple more inches in the space of 24 hours.

The ground shifted four inches in total, causing a long crack in the home. Unfortunately, that homeowner is not alone.

“There’s hairline cracks all over the place; 52 in adjacent properties,” said Cassidy.

Crews said they found cracks in several backyards. Workers expect the land to keep sliding down hill. Workers believe one possible cause of the slide could be a water leak underground, perhaps from a broken pipe.

“There’s obviously something happening in the ground. We don’t know yet, so that has to be investigated,” said Cassidy. “[We need to] figure out what the cause; is it hasn’t moved in 60 years, so why all of a sudden it’s moving?”

Martell bought his home for $2.1 million. He said he wants to figure out the cause so he can determine if he will ever be able to rebuild.

“The first day, you’re numb from it. Now it’s a little more reality of what’s this really going to really mean for my family,” said Martell.