Death of That '70s Show actress Lisa Robin Kelly is now being treated as 'suspicious' by authorities. See video below.

Lisa Robin Kelly passed away after being admitted to rehab, and her death may be suspicious.

Kelly, who stared on That 70s Show, died after years of alcohol abuse and drunk driving arrests. Thus, her passing seemed fairly cut and dry...but it is now being is investigated as "suspicious".

A new report says that the L.A. County Coroner and the L.A. County Sheriff have decided to conduct separate investigations to determine the exact cause of death.

The doctor who found the actress dead may have failed to contact the authorities for almost four hours.

Lisa Robin Kelly was pronounced dead at 8:07 AM, but the county coroner was not contacted until noon.

One initial report said that Lisa was not taking any withdrawal drugs and that there were "no drugs or alcohol in her room, no vomit in her airway and no obvious sign of trauma."

A source has claimed that the doctor at the rehab facility told the coroner that Lisa had died of an embolism.

However, although the coroner cannot confirm this until after an autopsy was performed.

In addition, the source alleges that Lisa's rehab doctor said that she was on detox drugs, but this may have been false.

A spokesman confirmed her death, saying, "She had been fighting demons for a while and finally lost her battle."

The autopsy was finished on Saturday by the L.A. County Coroner's Office. However, , the toxicology results will take another two weeks to complete. A security hold has been slapped on the case; no new information can be released.

Lisa Robin Kelly, 43, died in her sleep after being admitted to the treatment center for alcohol abuse earlier in the week.

Lisa's manager, Craig Wyckoff, said that prior to her death, Lisa was "hopeful and confident, looking forward to putting this part of her life behind her."

Wyckoff said,

'She was battling the addiction problems that have plagued her these past few years,' Wyckoff said.

He added, 'Cause of death has not been issued yet and no death certificate has been issued either.'

Watch video of "That 70s Show" HERE