Lindsay Lohan's Assistant To Be Questioned Monday In Witness Tampering Investigation

Lindsay Lohan's former assistant, Gavin Doyle, is scheduled to be interviewed by prosecutors on Monday regarding allegations of witness tampering, RadarOnline.com is exclusively reporting.

"After blowing off his meeting with Los Angeles City Attorney, Terry White, last week, Gavin Doyle is scheduled to meet with him on Monday," a source tells us exclusively.

"The prosecutor is looking into allegations that Lohan's attorney, Mark Heller, wanted Gavin to say that the car accident last summer, in which Lindsay was behind the wheel, was actually his fault. Heller allegedly told Gavin to say that photographers were chasing the duo en route to the Liz & Dick set, and he grabbed the steering wheel, causing her to crash into the cement truck driver.

"White is taking this very seriously. Heller and Doyle allegedly had the conversation in New York, and White will be turning over his findings to the New York State Bar Association, and other law enforcement, if necessary."

The source said Doyle was the passenger in Lohan’s Porsche last summer when she crashed into a truck in Santa Monica, CA. He had been fully cooperating with prosecutors, and he was expected to be a key witness at the trial, had it proceeded.

As we previously reported, the 26-year-old actress struck a plea deal in the case last Monday, which will send her to rehab for 90 days and prevent the need for a trial.