The crimes he committed while lurking in the shadows would eventually put Ted Bundy in the spotlight — and keep him there for more than three decades.

This year marks the 30th anniversary of the notorious killer's execution, but America's fascination with Bundy lives on. Most recently, Netflix brought him back into the public eye in a new movie, "Extremely Wicked, Shockingly Evil, and Vile," starring Zac Efron.

Bundy's ability to live a double life continues to be puzzling. How did he attend college, build a political career and have a long-term relationship all while assaulting and murdering at least 30 women between 1973 and 1978?

Psychology experts have been studying the infamous serial killer for several years.Those experts include Thomas Widiger.

"There has long been a fascination with psychopaths. Many of the more popular fictional characters exemplify psychopathy," he said. "These persons often exemplify true evil and one is drawn to view that, like one slows down to observe a traffic accident or enjoys watching a violent or horror movie."

Bundy's mental health and psychiatric state have long been called into question. Widiger, a professor in the Department of Pscyhology at the University of Kentucky, has been on a quest for answers.

"My research on Ted Bundy is more concerned with demonstrating the benefits of a dimensional trait model (the five-factor model in particular) for identifying and describing persons with personality disorders," he explained. "Ted Bundy is a good illustration of this in that the categorical descriptions of Ted do not entirely provide an accurate or individualized portrayal. He fails to have some of the features of the prototypic psychopath."

As a serial killer, was Bundy unique?

Bundy was particularly interesting, because he was charming and articulate. Many wondered, how could a clean-cut law student with no criminal record be responsible for dozens of murders?

He didn't fit the profile.

Bundy was also able to evade law enforcement. He was arrested, jailed on a charge of murder and then escaped — twice.

While the facts of the case are captivating, Widiger says Bundy was not unique in being a serial murderer.

"He was, for the most part, emotionally stable. A trait common to all psychopaths is the ability to be deceptive — to lie with ease. The classic phrase in psychopathy literature is that they wear 'a mask of sanity,'" he explained. "There is probably a serial murderer some place in the United States at any given moment. They can be very difficult to catch because there is no personal connection between them and the victim."

What do we know about Bundy's mental health?

Bundy received a mental health evaluation when he was on trial for the Florida murders. In fact, he was interviewed by Hervey Cleckley, who is considered to be the "father of psychopathy." He diagnosed Bundy as a psychopath.

By definition, psychopathy refers to "social predators who charm, manipulate and ruthlessly plow their way through life — completely lacking in conscience and feeling for others. They selfishly take what they want and do as they please, violating social norms and expectations without the slightest sense of guilt or regret"

Psychopath is a personality trait that falls under "antisocial personality disorder." People with antisocial personality disorder have a long-term pattern of violating the rights of others without any remorse.

Widiger says Cleckley's analysis is mostly accurate. "However, Bundy would also be diagnosed with necrophilia, paraphilia and sadism more precisely."

According to Widiger's research, Bundy had the following traits:

• antagonism (deceptive, manipulative, callous, exploitative and arrogant);
• extraversion (engaging and assertive);
• high conscientiousness (skilled, competent, thoughtful, organized and diligent); and
• low neuroticism (glib charm and fearlessness).

What does it mean to define Bundy as a "successful" psychopath?

Widiger has come to the conclusion, there are “successful” psychopaths — people who have the core characteristics of a psychopath (that is, the traits of antagonism), yet somehow manage to succeed in exploiting others while avoiding punishment.

"I would consider Ted to be a successful psychopath, because of his traits of high rather than low conscientiousness."

Though Bundy was executed three decades ago, Widiger believes continued research is a useful tool for learning more and dealing with predatory psychopaths.