AceShowbiz - Oksana Grigorieva resorted to recording her phone conversations with ex-boyfriend Mel Gibson in a bid to gather evidence for prosecutors in the event she was murdered. The former couple is locked in a bitter custody battle over baby daughter Lucia following a split earlier this year and Gibson's name has been dragged through the tabloids since the Russian singer accused him of attacking her during a heated argument in January.

Grigorieva claims she feared for her life after the alleged incident, when she is said to have suffered bruising and had two of her teeth knocked out. Tape recordings of her subsequent phone calls with Gibson have since leaked online and Grigorieva admits she felt the need to document the arguments because she was convinced she would end up dead, reports TMZ.com.

In a candid interview with TV newsman Larry King, she says, "I started taping it around 11 o'clock because I thought, 'I'm actually not going to live through the night'. I wanted my mother to be able to prove that if I'm dead that this is who did it."

However, Grigorieva denies Gibson's behavior was the result of booze - because the actor, who has battled alcohol issues in the past, was sober whenever they were together. She adds, "There was no liquor, not once. He never drank... I've never ever seen him drinking."

"That's why I keep saying on those tapes, 'You need medication'. He does need medication for the sake of our daughter. He needs to be treated." King's full interview with the Russian singer was due to air in the U.S. on Wednesday night, November 16.