from www.nydailynews.com – Jesse James has a new weapon in his custody battle against ex-wife Janine Lindemulder.

The West Coast Choppers owner has filed court documents revealing an e-mail exchange between his ex-wife and his sister, Julie James England, in which Lindemulder allegedly admits to drug use, prostitution and extraordinary jealousy of Sandra Bullock, reports TMZ.com.

James claims that the e-mails – which were exchanged between 2008 and 2009 – will prove that Lindemulder is unfit to care for their 6-year-old daughter, Sunny, TMZ reports.

In one e-mail, Lindemulder allegedly divulges that she has agreed to spend a night with a man for $25,000. “This is a form of prostitution,” England responds.

In another e-mail, Lindemulder reportedly begs James’ sister for the painkiller Vicodin. After England shoots her down, James’ ex writes, “I am so depressed, Sun is suffering, I can’t even find the energy to play with her. It’s 9:30 and I don’t even know what she ate today.” She added, “Not being awake makes everything better.”

Lindemulder further complained about Sunny’s relationship with James’ newly divorced wife, Sandra Bullock.

“All Sunny talks about is Sandy, Sandy! Wtf?!” she wrote.

Previously, Lindemulder has praised Bullock for her stepparenting skills.

“She packs perfect lunches,” she told Life & Style in December 2009. “She thinks of every little detail from sunblock to sanitary wipes and the perfect amounts of food. I can’t compete. If I could wish any stepmom for my daughter, it would be Sandra.”

James’ lawyer announced June 18 at a custody hearing that the 41-year-old biker is making a permanent move to Austin with his children in July, UsWeekly.com reports.

The next day, James told TMZ “the first and foremost” reason for the move is that his three kids want to be close to Bullock to continue their relationship with the 45-year-old actress.