Two mass shootings in California that killed 18 people this week could bring civil lawsuits, but legal experts predict some tough cases.

On Saturday night, a 72-year-old man shot 10 people and injured 10 others at a dance studio hours after a Lunar New Year festival in Monterey Park. One of the injured victims died on Monday, when another shooter in his 60s killed seven people and injured another at two separate locations—a farm and trucking facility—in Half Moon Bay. Authorities believe that incident is a matter of workplace violence.