According to the IRS: "The taking of money or property through fraud or misrepresentation is theft if it is illegal under state or local law.” That would include building contractor fraud, for example.
Unfortunately, the theft loss deduction is limited, as of 2018. "For tax years 2018 through 2025, if you are an individual, casualty and theft losses of personal-use property are deductible only if the losses are attributable to a federally declared disaster (federal casualty loss)."
See <a rel="nofollow" target="_blank" href="
https://www.irs.gov/pub/irs-pdf/p547.pdf">https://www.irs.gov/pub/irs-pdf/p547.pdf</a> for more information.
