Efren Saldivar is a suspect in the deaths of six elderly hospital patients whose exhumed bodies contained a drug that halts breathing.
The case against Saldivar, 31, includes two special circumstances poisoning and multiple murder which could lead to the death penalty or life in prison without possibility of parole if he is convicted.
Saldivar, who once called himself the "Angel of Death" and then recanted, had been under suspicion since early 1998 in deaths at Glendale Adventist Medical Center.
He was arrested Tuesday as he arrived at his job as an electrician's apprentice and was held without bail.
Toxicological tests revealed the presence of the drug Pavulon in the remains of the six victims although it was not part of treatment of five of those patients, said Los Angeles County District Attorney Steve Cooley.
"If you give the person the drug Pavulon and don't create an artificial means to breathe, they die," he said.
Glendale hospital spokeswoman Alicia Gonzalez said officials had no comment. But the hospital issued a letter to patients and visitors saying it had cooperated with police and that doctors met with more than 250 families to review medical records.
Attorney Terry M. Goldberg, who represents Saldivar in a half-dozen wrongful-death lawsuits, said his client is indigent and will need a public defender in the criminal case.
"It appeared to me that he was very disturbed, very distraught and very upset," Goldberg said. "I hope people will be patient in ferreting out the truth in this case."
Investigators have been tightlipped since the case began in March 1998, when the state Respiratory Care Board suspended Saldivar'license.
That month, Saldivar allegedly told police he committed dozens of mercy killings at the medical center between 1989 and 1997.
Police said Saldivar told them he was angry at seeing terminally ill patients kept alive. Saldivar, who worked at the hospital on and off over the eight years, initially told police that he killed only those patients who were unconscious, had a "do not resuscitate" order on their charts and appeared close to death.
He later said in interviews that he lied to police because he was depressed, suicidal and wanted to be sent to death row.
Investigators reviewed the deaths of 171 patients who died while Saldivar was working at the hospital. Fifty-four cases were eliminated because bodies had been cremated. Of the remainder, 20 deaths were determined to have been suspicious, and the paralyzing drugs were found in the bodies of six.
Relatives of Jose Alfaro Sr., 82, who died Jan. 4, 1997, after being hospitalized with severe pneumonia, emphysema and chronic pulmonary and arterial disease, said police told them that Pavulon was found in Alfaro's system.
His cause of death was originally listed as cardiorespiratory failure. His family has hired a lawyer to file a wrongful death lawsuit.
"Who is he (Saldivar) to kill?" asked his wife Cecilia Alfaro. "That was my husband. We were married in 1941. I was only 26. And this guy killed and he had no right to kill."