ABC News Investigations of the Year:

Potentially deadly rental cars, and a supermodel's 'blood diamonds.'

Dec. 28, 2010 — -- This week, the Blotter is reprising 10 different Brian Ross Unit investigations that made a difference in 2010. Today: Naomi Campbell is forced to take the stand in a war crimes trial, and renting cars at your own risk.

A Supermodel, a Dictator and Blood Diamonds

ABC News began covering the international war crimes trial of former Liberian president Charles Taylor several years ago, with numerous stories about the eccentricities of the ex-warlord, who is accused of using illicitdiamonds to pay for weapons that fueled the bloody civil war in the neighboring West African nation of Sierra Leone. But in 2010, when ABC News began pursuing the issue of some specific "blood diamonds" that had allegedly belonged to Taylor, the investigation led to a celebrity delivering important testimony against Taylor and the return of the long-lost gems.

In 1997, supermodel Naomi Campbell and actress Mia Farrow were guests of then-South African president Nelson Mandela when Charles Taylor showed up at the presidential mansion. Farrow told ABC News that Campbell had told her that representatives of the Liberian strongman had brought her a large diamond that night. Farrow also produced a photo of Taylor and Campbell together at Mandela's house.

Campbell declined to come to the international court in the Netherlands that is trying Taylor to testify about the gems, though the gems were believed to be important evidence that Taylor had been in South Africa using uncut diamonds to buy weapons. During New York's Fashion Week, ABC News producers confronted Campbell backstage and asked her if she'd ever received gems from Taylor. The supermodel denied receiving the jewels, slapped the ABC News camera aside and stalked out of the interview. The confrontation was part of a Ross Unit Investigation that aired on Nightline in April.

CLICK HERE TO WATCH THE NIGHTLINE REPORT.

CLICK HERE TO READ A BLOTTER STORY ON CAMPBELL AND THE 'BLOOD DIAMONDS'.

Impact:The ABC News report and the photo, which was entered into evidence, helped spark a subpoena that compelled Campbell's testimony in the Hague. She reluctantly appeared in court in August. On the stand she told the tribunal that she had, in fact, received a handful of "dirty" stones, uncut diamonds, from men she took to be representatives of Taylor in the middle of the night. She said she had given them to a representative of a Mandela charity, who confirmed that she did give him the diamonds and has been holding them. Prosecutors played excerpts of the April Nightline report during Campbell's questioning.

CLICK HERE TO WATCH A NIGHTLINE REPORT ABOUT CAMPBELL'S TESTIMONY.

Taylor has denied all charges against him, including giving Campbell diamonds. The trial is ongoing, with a decision from judges expected in 2011.

Taking Potentially Deadly Rental Vehicles Off the Road

As people hit the road this holiday season, they might be unaware of a surprising fact -- most rental car companies do not have policies in place to ensure that vehicles under safety recall are fixed before they're rented out. An ABC News investigation also revealed that there is no federal law requiring rental companies to repair recalled cars before handing the keys to consumers.

A Good Morning America report that aired on July 7 told how the lack of a stringent recall repair policy led to the tragic deaths of two sisters. Raechel and Jacquie Houck rented their Chrysler PT Cruiser in October 2004, one month after Enterprise received a recall notice that an underhood engine fire could result from a possible leak in the vehicle's power steering fluid.

CLICK HERE TO WATCH THE GOOD MORNING AMERICA REPORT

CLICK HERE TO READ THE ORIGINAL BLOTTER REPORT.

Raechel, 24, and Jacquie, 20, died instantly after their car caught fire and hit an oncoming semi-tractor trailer on Highway 101 in northern California.

Executives from Enterprise, the country's largest car rental company, admitted during testimony for a lawsuit filed by Raechel and Jacquie's parents that recalled cars were sometimes rented without being fixed.

During the case, the Houcks' lawyers discovered that the Santa Cruz, California branch of Enterprise had rented the same PT Cruiser three other times since the recall notice.

Other Enterprise executives testified that there was no companywide policy requiring cars under recall to be held back from rental.

After Enterprise's admission of negligence, an Alameda County jury awarded the family $15 million.

Impact:

At the time of the initial ABC News report, Avis and Hertz had no companywide policies regarding the repair of recalled vehicles, according to their spokespeople. Instead, the companies said they assessed safety recalls on a case-by-case basis. After the ABC News report aired, Hertz changed course and said it would no longer rent vehicles under safety recall to the public until they are repaired.

The publicity over the Houck case also led to action by the federal government. Last month, the National Highway Traffic Safety Administration (NHTSA) launched an investigation to determine how quickly rental companies repair vehicles that have been recalled for safety issues. NHTSA has sent letters to GM, Chrysler and Ford asking for details on the recall repair status of almost 3 million cars.

The Federal Trade Commission (FTC) is also currently considering a petition filed by the Center for Auto Safety -- and prompted by the Houck case -- that would prevent Enterprise Holdings from renting out vehicles that are still subject to a safety recall.

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