Eminent drug expert reveals how popular combination of street drugs can turn vulnerable Americans into CANNIBALS - as California man is arrested after eating a severed HUMAN LEG in broad daylight

Footage of a man gnawing at a severed human leg on the side of a busy street in broad daylight shocked the nation this week - drawing speculation that the national drug crisis is to blame.

Video taken in Wasco, California, shows 27-year-old Rosendo Tellez picking up the leg, seemingly biting it and then waving it around on the sidewalk before police arrived.

Full arrest details have not been made available, but the internet is ablaze with theories about the potential involvement of drugs currently dominating the illicit drug supply, specifically xylazine and fentanyl.

Forensic toxicologist Dr Bruce Goldberger, who worked with police on the two horrific cases in Florida that involved disturbed people eating other’s faces, told DailyMail.com that he understood the instinct to suspect those drugs.

But he said meth, crack cocaine, or bath salts, would actually be the most likely culprits, given that stimulants can bring on a powerful state of psychosis, or total severance from reality, that other drugs like fentanyl, which is a sedative, cannot. 

However, if fentanyl is combined with other drugs, it can enhance the effects of them.

Horrified onlookers watched on as the man bent over and sniffed the leg before reportedly biting into it and then waving it around on the streets of Wasco, California 

Rosendo Tellez was seen walking down the street, waving the limp severed leg around, carrying it by the foot

According to Dr Goldberger, Tellez’s cannibalistic behavior is not ‘characterized in the medical literature. This is so unusual, so aberrant that it’s not something that could be readily studied.’

He added: ‘When you hear about these cases, sometimes you think immediately if a drug or drugs were involved.’

Stimulants, such as methamphetamine or crack cocaine, for instance, are the most likely class of drugs, Dr Goldberger said. 

Bath salts, a type of stimulant drug that people either snort, smoke, or inject, are now infamous for links to two deranged attacks in which people ate others’ faces off.

Dr Goldberger told DailyMail.com that in a psychotic state, eating another's flesh may be seen as necessary for self-defense or survival if the person is convinced they'll starve otherwise.  

In this altered state of mind, the neurotransmitter dopamine, responsible for rewarding survival-boosting behavior like eating, can exacerbate psychotic delusions.   

Because of their effects on dopamine levels, stimulants are most likely to cause psychosis, a state in which one becomes separated from reality, and is prone to deranged or violent behaviors, potentially escalating to cannibalism, he said.  

Stimulants also drastically impair the user’s judgment, making them more impulsive and uninhibited, and create a state of hyperagression that could extend to violence. 

Rosendo Tellez was arrested for removing human remains from the site of an Amtrak crash earlier that day that had struck and killed one person, as well as for possession of controlled substance paraphernalia, and one felony offense of violating probation, according to arrest records.

Mother of Miami cannibal says 'My son was no zombie' 

The mother and brother of Rudy Eugene, the man nicknamed the 'Maimi Cannibal' said he would 'never' be capable of attacking another person and chewing his face off. 

The grim footage was captured by nearby construction worker Jose Ibarra, who said: ‘On the video that we have, it shows clearly that he started chewing on the leg and everything.’

Tellez was homeless at the time of his arrest and had at least half a dozen other misdemeanor charges on his record, mostly for drug and alcohol-related offenses.   

At the same time, Dr Goldberger said it was also likely that Tellez was not on drugs but in fact was severely, violently mentally ill.

He said: ‘In the cases I’m familiar with, no drugs have been involved. It was underlying behavior that led to cannibalism that has no association with a drug or drugs.’

One of those cases involved 31-year-old Rudy Eugene in Miami, who tore off pieces of 65-year-old Ronald Poppo’s face. Eugene, a diagnosed schizophrenic, was later found to have used marijuana, not bath salts as was popularly assumed when the event made national headlines.

Dr Goldberger said the marijuana in his system was ‘nothing significant or important’ in terms of influencing his behavior.

The other was that of Austin Harrouff, a Florida State University student who, at age 19, killed a couple and ate one of their faces. He was found to be incompetent to stand trial by reason of insanity.

Dr Goldberger said: ‘There were many tests that were done by the state, the FBI, over the course of a few years, because drugs evolve over time. There could be drugs in someone's blood today that we’ve never seen before.’

He stressed that fentanyl and xylazine would not have caused the behavior shown in Mr Ibarra’s viral video. Those drugs ‘don’t cause psychosis.’

While Mr Tellez’s toxicology report has not yet been provided, whatever is in it could end up providing few answers.

Standard drug tests at jails look for standard drugs of abuse, including opioids, cocaine, ecstasy, and other stimulants. But they will not pick up other designer drugs that could play a role in causing psychosis, such as spice, bath salts, synthetic marijuana, or K2.