Updated

The family of a man slain by a former Bay Area transit police officer early New Year's Day filed a $50 million wrongful death lawsuit against the officer and the transit agency.

Oscar Grant's family is suing the Bay Area Rapid Transit agency, former officer Johannes Mehserle, BART police chief Gary Gee, and officers Tony Pirone and Marysol Domenici.

Grant family attorney John Burris said the shooting was intentional. He said Grant was unlawfully detained, arrested and deprived of urgent medical care after he was shot by Mehserle on a train station platform in Oakland.

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Filed in U.S. District Court in Oakland on Monday, the lawsuit said the officers' conduct was "extreme, unreasonable and outrageous." Grant and his friends were pulled off a train by BART police investigating reports of a fight.

In January, Grant's family filed a $25 million legal claim against BART. But Burris said the lawsuit is seeking double that amount since the family has received more information surrounding the shooting.

"This is more egregious than I initially thought," Burris said. "Since then, I've had the benefit of listening to more interviews, seeing more tape and I have a fuller understanding of the facts that Mr. Grant's civil rights were violated long before he was shot."

Dale Allen, an attorney representing BART, said Pirone lawfully detained Grant and his friends. He called the shooting "a tragic accident," adding that BART has discussed mediation with Burris "in hopes of bringing some closure to the Grant family."

The shooting — which grabbed national attention after cell phone videos of the incident began circulating on the Internet and television — continues to cause community outrage and has led to numerous protests and arrests.

Under heavy police presence, more than 150 people Friday joined Grant's family, his girlfriend Sophina Mesa and their 4-year-old daughter for a peaceful celebration in his hometown of Hayward on what would've been Grant's 23rd birthday.

Mehserle has pleaded not guilty to murder and is free after posting $3 million bail. His preliminary hearing is scheduled for March 23.

There is a gag order in the case. But Mehserle's attorney, Michael Rains, has previously said Mehserle his client had meant to fire his Taser when he fired a single shot with his pistol.

Rains has argued against the court-imposed gag order, saying it prevents him from fighting negative publicity about his client which could prejudice potential jurors.

Also named in Monday's lawsuit is Pirone, who has been identified as hitting Grant in the head shortly before Grant was fatally shot. The suit also says Pirone threatened to use his Taser on Grant and his friends if they did not comply will his orders.

Pirone's attorney, Bill Rapoport, said that Grant provoked Pirone's blow by trying to knee Pirone at least twice. Rapoport does not think his client will face criminal charges.

"Officer Pirone has no civil liability or nor criminal culpability in relation to this incident," Rapoport said Monday. "He did nothing wrong."

Domenici is accused of repeatedly pointing her Taser and threatening to stun them in the face.

Pirone and Domenici remain on paid leave. BART is conducting a criminal investigation of the officers' actions which will be turned over to Alameda County prosecutors to decide on possible charges.

Click here for more on this story from KTVU.com in San Francisco.