Mark Geragos’ name typically comes up when celebrities are in trouble, but who is he exactly?

The defense attorney has worked for clients accused of murder, abuse and lying to police, but according to a report from The Wall Street Journal and an unnamed source to The Associated Press, he could be a co-conspirator in a federal extortion case involving Michael Avenatti.

>> Read more trending news

Geragos has not commented on WSJ’s report.

Here are things to know about Mark J. Geragos' career, which includes a client list made up of Nate Dogg, Winona Ryder, Diddy, and Barry Bond's personal trainer Greg Anderson.

Defended Winona Ryder 

After Oscar-nominated actress Winona Ryder faced shoplifting charges after being detained by security officers in December 2001. Geragos represented her in the six-day trial, according to The New York Times.

Winona Ryder listens as the verdict is read at the Beverly Hills Municipal Court on the eighth day of her shoplifting trial on November 6, 2002 in Beverly Hills, California. She  was found not guilty of burglary  charges, guilty of vandalism and felony grand theft charges stemming from her shoplifting arrest December 12, 2001 at a Saks Fifth Avenue store in Beverly Hills.

Credit: Pool

icon to expand image

Credit: Pool

In November 2002, Ryder was found guilty of grand theft and vandalism for taking more than $5,500 worth of designer goods from a Beverly Hills Saks Fifth Avenue. She was found not guilty of commercial burglary, but was as sentenced to three years' probation, 480 hours of community service, $3,700 in fines and $6,355 in restitution to the store. She was ordered to get drug counseling and psychological counseling.

Defended Scott Peterson 

Geragos unsuccessfully defended Scott Peterson's death penalty case after becoming his attorney in May 2003. Peterson was found guilty of first-degree murder for the death of his wife, Laci Peterson, and second-degree murder for the death Laci Peterson's unborn son.

Defended Michael Jackson

In February 2003, the King of Pop hired Geragos when accusations emerged that he may have molested a boy. He was ultimately fired from Jackson's legal team in April 2004, reportedly because he was too busy with the Peterson case.

Jackson was found not guilty on all charges in 2005.

Michael Jackson arrives to the Santa Barbara County courthouse for his molestation trial April 14, 2004. Jackson was charged in a 10-count indictment with molesting a boy, plying him with liquor and conspiring to commit child abduction, false imprisonment and extortion.

Credit: Pool

icon to expand image

Credit: Pool

Defended Chris Brown

When Chris Brown faced assault charges after brutally attacking singer Rihanna, he enlisted Geragos' help. Geragos reached a plea deal for his client in 2009, and Brown was sentenced to five years of probation and had to serve 180 days in jail or the equivalent in "labor-oriented service."

Singer Chris Brown and attorney Mark Geragos attend a progress hearing at Los Angeles Superior Court on October 23, 2014.  Brown was first placed on probation after the 2009 domestic violence case in which he plead guilty to assaulting his then-girlfriend, Rihanna.

Credit: Pool

icon to expand image

Credit: Pool

Under the plea deal, Brown pleaded guilty to one count of assault with the intent of doing great bodily injury. Brown had several run-ins with the law after, violating his probation -- resulting in jail time -- and being accused of rape. No charges were filed after that accusation. Geragos represented him in a number of trials and has said he considers the singer a son.

Defended Jussie Smollett

"Empire" actor Jussie Smollett hired Geragos to represent him against the 16 felony disorderly conduct charges he faces after he allegedly staged homophobic and racist attack in January. Smollett allegedly coordinated with two brothers who Chicago police say he paid to attack him. Smollett pleaded not guilty, and on March 26 Cook County prosecutors dropped all charges.