He was once the top cop of New Orleans pedophile unit. Now he's been arrested for not registering as a sex offender.

Stanley Carl Burkhardt, 68, the convicted pedophile who oversaw the New Orleans Police Department child sex abuse investigations unit between the 1970s until 1987, before he was revealed to be a pedophile himself, was arrested last week for not registering as a sex-offender.

And that's just the tip of it.

Disturbing new details have emerged.

Some members of the public and law enforcement apparently suspect Burkhardt could possibly be a serial killer linked to the death of three boys in the late 1970s and one in the early 1980s.

Burkhardt's arrest comes must months after one of two men who previously accused the former sex crimes cop of sexually molesting him decades ago saying publicly that Burkhardt also bragged about playing a part in killing a teenage boy found dead floating in the Mississippi River in New Orleans in 1982.

That prompted the New Orleans Police Department's cold case homicide team to take a fresh look at the drowning death of the victim Edward Wells, according to NOLA.

And that investigation police investigators to begin re-examining the cases of three other teenage boys who were killed between February 1978 and November 1979.

The three teens were known to frequent the same section of the French Quarter as Wells was thought to hang out and where Burkhardt was also thought to frequent.

Authorities investigating those deaths have avoided naming Burkhardt a suspect in any killing or death — or calling him a suspected serial killer.

But a Louisiana State Police detective who obtained the warrant which led to Burkhardt's recent arrest on Wednesday is one of the same investigators investigating the deaths of Daniel Dewey, Raymond Richardson and Dennis Turcotte.

Those were the three teen victims found dead during the 21 month span in the late 1970s.

Recently, detectives also searched Burkhardt's home in connection with online comments under photos of young boys online.

That investigation was launched after an anonymous source informed state troopers in June that Burkardt was using the photo-sharing website Flickr to leave "disturbing comments" under pictures of young boys, which were published by other users.

"Long legged laddie looking for luv,” one comment read, which was posted under the user name "Stan Burkhardt."

"Boys in their unguarded moments are essentially sensual," another comment from Burkhardt's account read under a young boy in a T-shirt, according to State Police investigator Raymond Hughes.

Investigators determined an email address tracing back to Burkhardt was associated with the user name in question, according to Hughes.

Detective Hughes also said secured evidence showing the user name from a cell phone accessed by Burkhardt as well as from a library computer as linked to him.

The library's security cameras also captured him at the library at the same time the posts were made.

Adding to Burkhardt's troubles, what apparently got him arrested was somehow removing a stamp on his driver's license which identified him as a sex offender when he applied for a job.

The stamp was found to be missing when he applied and was hired for a job at Harrah's Casino in the spring.

However, he was suspended from his job on July 1 after a background check revealed he was a sex offender.

And that discovery by authorities prompted detective Hughes to request Orleans Parish Magistrate Commissioner Brigid Collins to sign a warrant accusing Burkhardt of failing to register as a sex offender, or to provide notification that he was one.

Collins signed off on the request on Monday.

Stanley Burkhardt, who largely ran the NOPD’s child abuse investigations in the 1970s and 1980s, was booked into jail Wednesday.

Burkhardt was fired from the department and sent to prison in 1987 after his conviction for mailing explicit images of underage boys to undercover officers.

He was also found guilty of raping a 9-year-old relative and receiving child pornography.

That landed him in federal prison.

Authorities thought he was so dangerous to the public then, they wanted to keep him behind bars.

So they utilized a law to secure lifelong sentences for offenders deemed to be "sexually dangerous."

In 2011, a federal judge in North Carolina determined Burkhardt was indeed "sexually dangerous" and ordered him to be imprisoned for life.

But after only four years of treatment, a different judge ordered him to be set free under supervision.

During a 2011 civil proceeding, a man named Richard Windmann testified that Burkhardt sexually abused him as a teen.

Windmann also told reporters last year how Burkhardt would often brag about killing Wells and would show him photos of Wells' dead body and threaten he'd do the same to him .

"Do you want to end up like Eddie?" Burkhardt would tell the then teenage boy.

At that time, Burkhardt was in charge of investigating the murder of Edward Wells.

At the same time in 2011, a man by the name of Vic Groomer informed police that he was about 8-years-old when Burkhardt began sexually abusing him.

Groomer said Burkhardt would intimidate him as well and menacingly show him crime-scene photos of various dead boys, including ones he says appeared to look like Edward Wells.

So far, authorities have not booked Burkhardt on accusations of abuse made by Groomer or Windmann, which date back to the 1970s.

"I’m especially grateful to the Louisiana State Police for keeping this guy under a microscope and yeah Stanley that’s been happening, there’s a lot of people that have been watching you and I’m determined as are a lot of other people that this isn’t going to happen again," Windmann told Fox 8.

But it looks like they're on to something.

Burkhardt, who could face prison time if convicted of breaking Louisiana's sex-offender registration law, has been released on a $10,000 bail.