The Los Angeles County coroner's office will investigate the death early today of conservative writer and activist Andrew Breitbart at the age of 43, the Los Angeles Times reports.

The bombastic right-wing activist died of what his website called "natural causes."

The Times says an autopsy will be conducted to help determine a specific cause of death.

Original post: "Andrew passed away unexpectedly from natural causes shortly after midnight this morning in Los Angeles," Larry Solov, president of breitbart.com, says in a statement. "We have lost a husband, a father, a son, a brother, a dear friend, a patriot and a happy warrior. Andrew lived boldly, so that we more timid souls would dare to live freely and fully, and fight for the fragile liberty he showed us how to love."

Breitbart, a Tea Party favorite, was an outspoken critic of the mainstream media. His efforts were behind controversial investigations that led to the resignations of former Rep. Anthony Weiner and former Agriculture Department official Shirley Sherrod.

His website also featured a 2009 hidden-camera sting video that brought embarrassment to the community group ACORN. The videos show ACORN staffers purportedly offering advice on taxes and other issues to actors posing as a prostitute and pimp.

Breitbart was walking near his house in the Brentwood neighborhood of Los Angeles shortly after midnight when he collapsed, his father-in-law Orson Bean says, the Associated Press reports.

Someone saw him fall and called paramedics, who tried to revive him. They rushed him to the emergency room at UCLA Medical Center, Bean says.

Breitbart had suffered heart problems a year earlier, but Bean says he could not pinpoint what happened. "I don't know what to say. It's devastating," Bean tells the AP.

Update at 2:13 p.m. ET: The Los Angeles County coroner's office will review Breitbarth's death and will conduct an autopsy, The Los Angeles Times reports.

Given his young age -- he was 43 -- and the unexpected manner in which he died, authorities will conduct an autopsy to help determine a specific cause of death.

He is survived by his wife Susannah Bean Breitbart, 41, and four children.

The Los Angeles Times reports that Breitbart spent 10 years as editor of the conservative Drudge Report and helped to launch the Huffington Post, before striking out on his own in 2005 to launch his news aggregation site Breitbart.com.

The site was designed, the Times writes, to counter what Breitbart described as the "bully media cabal" that, he charged, ignored stories challenging prevailing liberal orthodoxy. His goal, he often boasted, was to "destroy the institutional left," the newspaper says.

Breitbart was at the center of two video controversies in recent years — one that led to the firing of Sherrod over an edited video of what appeared to be a racist remark, and another that embarrassed the community group ACORN when workers were shown purportedly counseling actors posing as a prostitute and pimp.

In the Sherrod incident, Breitbart is known for disseminating an edited video that showed the Agriculture Department official making what appeared to be racist remarks, the AP reports.

Sherrod, who is black, was fired from her job as Georgia state rural development director in July 2010 after the video surfaced. In it, she is seen telling a local NAACP group that she was initially reluctant to help a white farmer save his farm more than two decades ago, long before she worked for USDA.

Missing from the clip was the rest of the speech, which was meant as a lesson in racial healing. Sherrod told the crowd she eventually realized her mistake and helped the farmer save his farm. She has since filed a lawsuit against Breitbart.

Although he strongly defended himself over the Sherrod incident, he told Newsweek:"If I could do it all over again, I should have waited for the whole video to get to me."

According to TPM.com, Sherrod issued this statement today: "The news of Mr. Breitbart's death came as a surprise to me when I was informed of it this morning. My prayers go out to Mr. Breitbart's family as they cope through this very difficult time."

Matt Drudge issued this statement:

DEAR READER: In the first decade of the DRUDGEREPORT Andrew Breitbart was a constant source of energy, passion and commitment. We shared a love of headlines, a love of the news, an excitement about what's happening. I don't think there was a single day during that time when we did not flash each other or laugh with each other, or challenge each other. I still see him in my mind's eye in Venice Beach, the sunny day I met him. He was in his mid 20's. It was all there. He had a wonderful, loving family and we all feel great sadness for them today... MDRUDGE

Here is Solov's full statement announcing Breitbart's death: