An actress who appeared on the hit TV medical drama ER and starred in the film Stand and Deliver was fatally shot by police officers in Southern California after they say she pointed a replica handgun at them.

Vanessa Marquez, who gained attention last year when she said George Clooney helped blacklist her from Hollywood, died at a hospital following Thursday's shooting at her apartment in South Pasadena, just outside Los Angeles.

South Pasadena police officers were responding to a call from Marquez's landlord that she needed medical help when they found her having a seizure, Lt. Joe Mendoza with the Los Angeles County Sheriff's Department said Friday.

Paramedics treated Marquez, 49, who improved and began talking with three officers and a mental health clinician who spent an hour and a half trying to talk her into getting additional medical help, both physical and mental, Mendoza said.

Marquez became uncooperative, appeared unable to care for herself and seemed to have mental health issues, he said.

BB gun prompted officers to shoot

At some point, Mendoza said Marquez got what turned out to be a BB gun and pointed it at the officers, prompting two of them to shoot.

"It looked like a real gun," he said, adding that it's unclear where the gun was during her lengthy interaction with police.

The officers were wearing body cameras but footage won't be released for at least six months pending the investigation, Mendoza said.

Terence Towles Canote, a close friend of Marquez's, said the actress was having health and financial problems but that she showed no signs of depression or other mental troubles.

'This is not a woman who wanted to die'

She talked about her dream of winning an Oscar one day and was hopeful for a career comeback despite her medical struggles, he said.

"She was looking forward to life," Canote said. "This is not a woman who wanted to die."

Marquez posted extensively on Facebook and in other outlets about her health problems, saying she was terminally ill and had seizures and celiac disease, an autoimmune disorder that can damage the small intestine with the ingestion of gluten.

In 2014, she said in an online post that she had spent her entire life savings on doctors and hospitals who didn't properly treat her and that she couldn't work or "do most basic everyday functions."

Criticized Clooney

Marquez gained attention last year after tweeting that George Clooney helped blacklist her from Hollywood when she complained about sexual harassment and racist comments among their ER co-stars. Clooney said in a statement to US Weekly at the time that he was just an actor on the show and was unaware of any blacklist.

"If she was told I was involved in any decision about her career then she was lied to," he said. "The fact that I couldn't affect her career is only surpassed by the fact that I wouldn't."

Marquez also appeared on episodes of Seinfeld, Melrose Place and Malcolm & Eddie but her career largely fizzled after ER.

One of her posts talked about being grateful to be a part of Stand and Deliver, a 1988 film about a math teacher who motivated struggling students at a tough East Los Angeles high school.

"If you're truly fortunate, you get to live your dream and do the work you were put on this Earth to do," she wrote. "If you're really, really fortunate you do a film that makes history and affects the lives of millions of people ... It will live on long after we're gone."