US federal investigators have condemned Apple's internal inquiry into the backdating of stock options at the company, The Times claims this morning.

According to the report, the US Securities and Exchange Commission and the US Department of Justice have asked Apple to hand over more documents explaining how company executives were granted the options.

As previously reported Apple CEO Steve Jobs was last week called in for questioning, in particular regarding some options granted to him in December 2001 that were backdated to October.

The company falsified records regarding this grant. The lawyer who drew up false records has now been let go from Apple, but has claimed she was acting under orders from Apple General Counsel Nancy Heinen, who has also quit the company.

In a related report, it has been revealed that Jobs waited eight months to declare the December 2001 options — perfectly legitimate in itself, but a longer-than-usual wait for a filing from an Apple executive.

According to The Times, a SEC source said: “To have a representative from the Department of Justice — a criminal prosecutor — attend an interview with a company CEO is a very serious matter. This is not a polite request for information."

The investigation is likely to proceed "for some time".