Oksana Grigorieva’s legal team has suffered another blow -- her top family law attorney Allen Shiftman has quit the case, RadarOnline.com has exclusively learned.

He delivered the sudden news to the Russian musician a short time ago.

EXCLUSIVE PHOTOS: See The First Photos of Mel and Oksana In a Passionate Embrace On The Beach

Shiftman, a top Los Angeles family law specialist, replaced Mitchell Jacobs, who resigned last month, citing frustration with some of Oksana’s other legal advisors.

Jacobs had replaced high powered Hollywood attorney Sorrell Trope, who Oksana sacked — after sacking two other firms.

Oprah Winfrey could emerge as a key player in the criminal investigation into Mel Gibson's alleged beating of Oksana Grigorieva.

The Russian musician, 40, filmed a ‘pre-interview’ with the talk-show queen’s producers at her Sherman Oaks, California, home, RadarOnline.com has learned.

PHOTOS: Oksana Grigorieva Has A Mother-Son Movie Date

Los Angeles District Attorney investigators are interested in what Oksana may have said and whether it was consistent with her claims that the Lethal Weapon star punched her twice, while holding their infant daughter Lucia.

Oksana Grigorieva's lawyers have finally snagged a sit-down interview with Mel Gibson, and the all-important deposition will take place next Monday, RadarOnline.com has learned.

But lawyers for the Russian musician are almost certain to hear stone-cold silence when the Lethal Weapon star is grilled about allegations he punched his ex-lover while she held their infant daughter Lucia.

PHOTOS: Oksana Grigorieva Has A Mother-Son Movie Date

Oksana Grigorieva’s legal team is in crisis after her top family law attorney suddenly quit the case before a critical deposition, RadarOnline.com has exclusively learned.

Mitchell Jacobs — a family law attorney who has been a Board Certified Family Law Specialist since 1986 — handed in his resignation on Sunday afternoon, citing frustration with some of the Russian musician’s other legal advisors.

PHOTOS: Oksana Grigorieva Has A Mother-Son Movie Date

It is a brutal blow to Oksana, 40, who is scheduled to be questioned in another deposition on Thursday.

Oksana has claimed her former lover, Oscar winning actor Mel Gibson, punched her in the face while she held their infant daughter Lucia.