Federal prosecutors are investigating Tesla’s use of company funds on a secret project that had been described internally as a house for Chief Executive Elon Musk, the Wall Street Journal reported Wednesday, citing people familiar with the matter.

Neither Musk nor a spokesman for the US Attorney’s office in Manhattan immediately responded to requests for comment.

No dollar figures were disclosed, and the newspaper said the house was near Austin, Texas.

The Journal reported in July that Tesla board members had investigated whether company resources were misused on the effort.

The Securities and Exchange Commission has also opened a civil probe, the Journal reported.

An SEC spokesperson said the agency does not comment on the existence or nonexistence of a possible investigation.

The probes are in their early stages and may not lead to charges, the Journal said.

Prosecutors were seeking information about personal benefits to Musk, the world’s richest man, as well as how much Tesla spent on the project and what it was for, the Journal reported.

The paper said prosecutors were also looking into a lower-than-expected driving range on Tesla’s electric vehicles.

Reuters reported in July that the cars often fail to achieve their advertised range estimates and projections reported by the cars’ own equipment, citing experts who tested or studied them.