America has been captivated by the new podcast "Serial" — a week-by-week breakdown of a murder case that was supposedly solved more than a decade ago.

"Serial" is a spinoff of "This American Life." Instead of talking about several stories in one episode, each season will follow only one story.

For the first season, journalist Sarah Koenig is diving into the murder of Baltimore high school student Hae Min Lee. She was murdered in January 1999, and her body was found in a shallow grave in a park about a month later.

Her ex-boyfriend and classmate, Adnan Syed, was eventually convicted of her murder. He has always proclaimed his innocence, and Koenig is exploring whether he's telling the truth.

Police charged Adnan with Hae's murder after his friend Jay, a former classmate of Hae's and Adnan's, told police that Adnan told him about the murder and enlisted his help in burying Hae's body.

"Serial" has a big audience on Reddit, and Redditors have created an entire subreddit dedicated to discussing their theories and trying to determine who killed Hae.

We've complied some of the best theories surrounding the case.

Warning: Spoilers below.

Theory #1: Adnan hired Jay to kill Hae, and Jay turned on him.

Many "Serial" fans believe Jay is more involved in Hae's death than he let on.

Jay knew details about Hae's manner of death and burial that suggested he was involved in some way. He claims he just got dragged into the aftermath of the murder by Adnan, but some think he was also involved in her murder — not just burying her body.

Redditor zmachine52 explains:

Adnan had/hired/convinced/coerced/ etc. Jay to kill Hae.

Does this solve all of the issues?

They are both guilty. Therefore neither can implicate one another. Jay cuts a plea deal to get himself off the hook, meanwhile Adnan is able to (somewhat) plausibly deny much of [the] issues at hand, yet would still be guilty of murder 1, if discovered.

This could help explain the the timeline issues, the character issues, the "alibi", Jay's inconsistent stories (as he had to work Adnan into the story to cut his plea), the burial, the shovels, the car, cleaning the items, etc.

Basically a good dude somehow convinced a shady friend to commit murder for him. They are essentially both guilty, but one was able to plea out. The other is caught in a catch 22 but with lots of plausible deniability.

This is an interesting theory, but it doesn't quite explain why Adnan wouldn't have a more solid alibi prepared or turn on Jay once he figured out that Jay sold him out to the police.

Theory #2: Jay and his friend Jenn did it.

Redditor justforserial argues that Jay and Jenn, a friend of his and Adnan's, might have committed the murder.

Justforserial theorizes that Jay and Jenn might have been carrying on an affair behind Jay's girlfriend Stephanie's back and Hae knew about it. Therefore, the pair killed Hae to shut her up.

Here's the theory:

Hae knows that Jenn and Jay are together behind Stephanie’s back and they are both worried she will expose them. At some point during this time Jenn pages Hae. Hae calls her back from a phone at the school. Jenn asks her to meet her at the Best Buy parking lot so that they can talk. Jay agrees to the plan because he doesn’t want Hae to expose their secret. Jenn and Jay drive together to best buy.

At 2:36 Adnan uses the phone in the library or a pay phone near the library and tries his own phone again to reach Jay and Jay answers but immediately hangs up the call. Right after this time Asia sees Adnan in the library and they start talking.

Hae meets Jenn and Jay in the parking lot, she’s surprised to see Jay because she expected it just to be Jenn. Jenn and Jay get into Hae’s car. Hae is sitting in the driver’s seat, Jenn in the front seat and Jay in the back. The interaction starts as a conversation but escalates quickly. Jay and Jenn hadn’t intended to kill Hae, but they had had a conversation that if she wouldn’t agree to keep quiet they would kill her. They had intended at first just to scare her and intimidate her into keeping their secret. However, Hae is strong willed and she argues back about how Stephanie is one of her best friends and she is going to tell her no matter what they say. Jay sees red, because Hae is threatening his relationship, and he reaches around her neck and strangles her in the car. Jenn holds down Hae’s arms while she is being strangled, and this is when she kicks the blinker off.

Justforserial also has explanations for the various other cellphone calls from Adnan's phone that occur before and after the murder, but this theory as a whole seems farfetched.

Theory #3: Adnan is a psychopath.

While listening to "Serial," it's important to keep in mind that we don't know everything. We've been given a lot of information about the case, but there are also many people we haven't heard from, including some of Adnan's friends.

Someone who claims to have known Adnan growing up writes on Reddit that several of Adnan's former friends saw psychopathic tendencies in him. Because the Muslim community Adnan grew up in is so tight-knit, according to this person, those who were close to Adnan might have been afraid to speak out over fear of retribution from their community.

So, although Adnan seems charming and smart when he talks to Koenig, and she has admitted that she thinks he's a good guy and likes talking to him, some still think he's guilty and has managed to manipulate those around him. Friends of his might have been reluctant to come forward with their true feelings about Adnan over fear of being ostracized from their community for implicating Adnan in Hae's murder, the theory goes.

Redditor swframe666 explains why Adnan had to be the killer:

The one fact that is not in dispute is that Jay knows too much about the crime and has communicated his knowledge about it in a way that strongly supports that he knows the killer. The killer isn't an unknown person.

I think there is only one source of information that we need to review. It is the statements that Adnan makes about what he and Jay did together. Adnan statements indicates that he was with Jay that day and Adnan is the only person with Jay that doesn't have a strong alibi. And Jay's information very strongly indicates that he was with the killer that day.

The logistics of the cars, shovels and cell phone strongly indicates there was another person involved and the only other person that could have been involved is Adnan. To happen in a short time frame, the murder had to have been premeditated. The car and cellphone exchange means that it couldn't have been spontaneous. Another person couldn't have gotten to Hae so quickly given they would not have known that the car and cellphone was going to be exchanged that day. In addition, no other person Jay is in contact with that day is known to be involved with Hae.

Hae had to have been killed just after school and had to have been killed by someone she knew and trusted. Given the short time frame, Adnan is the only one who could have gotten that close to Hae that quickly. There is no evidence that Jay could have killed Hae so quickly and easily given that they are not known to be close friends.

I think Jay's testimony is inconsistent because he is an accomplice and he is trying to frame the events in a way that doesn't implicate himself. I think Adnan didn't turn on Jay because Adnan didn't think he would lose the case.

I don't know Adnan's motives. I don't know why Adnan would pick someone who he was not close to help cover up a murder. Jay turned on Adnan very quickly. I don't think any other facts matter because Jay must know the killer, must have been involved in the murder and the only other person with Jay is Adnan.

This is certainly possible, since psychopathy generally makes people more predisposed to committing violent crimes. But psychopaths are also very rare. One expert has estimated they account for only 1% of the US population.

Theory #4: Adnan was trying to frame Jay for the murder.

Many have speculated Adnan and Jay were in it together. Jay knew a lot of intimate details about the murder and admitted to police that he helped Adnan bury Hae in Leakin Park.

Redditor miketetzu's goes a step further and reasons that Adnan was trying to frame Jay and Jay figured it out, which is why he sold Adnan out to the police:

Adnan murdered Hae, and Adnan's plan was to set Jay up for the murder. However, something happened: perhaps Jay got nervous, perhaps Adnan let something slip, or they had a falling out of sorts. Jay decided to sell Adnan out before Adnan sold him out, hence Adnan's "you're pathetic" aside at trial.

There are a lot of things that led me here, such as:

i. People say Jay and Adnan weren't good friends, and Adnan states this, too. So why does Jay have Adnan's cell phone, and why are they hanging out so often around the time of the murder? (Answer: Adnan planned to set Jay up for the crime, and so had to get close to Jay in order to get him involved.)

ii. Why doesn't Jay come forward right away, a question asked by the cops as well? (Answer: Jay initially doesn't come forward because he thinks he and Adnan are in it together, but subsequently gets nervous.)

iii. Why doesn't Adnan call Hae after her death? (Answer: Because he knows she's dead, obviously. This is just common sense, has nothing to do with my theory.)

iv. How does The Nisha Call fit into the theory? (Answer: I don't think this is something we can completely know, but I have two guesses: one is that the call was an accident by Adnan around the time of the murder. He realizes this is a potential problem for him, and so weeks later has Jay talk to Nisha from his cell phone to corroborate that Jay and Nisha once spoke from Adnan's cell phone. I don't think he thought this through all the way, but the reality is that it DOES muddle things; it doesn't have to exonerate him in order to help him. The second guess: Jay makes the call intentionally on the day of the murder, since the other six calls are to people he knows, so Adnan can't say he wasn't with them. Perhaps Jay makes the call and hands the phone to Adnan, who is not at practice, or maybe Jay makes the call and pretends to be someone else. Maybe Jay pretends to be the pizza man to Nisha’s mom. Adnan realizes the problem with this later after reviewing his call log, and see above for how he deals with it.)

v. As a statement: I also feel like this theory explains Jay's constantly changing stories. Jay realizes, either via conversations with the police that we're not aware of yet, or just as a sense, that he might be able to get off completely free and clear. He understands that he can pin the whole thing on Adnan, and slowly works his way to THAT story through the reactions of the detectives.

This theory seems a little wild, but it's not implausible that Jay was involved in Hae's death since he knew so much about her murder.

Theory #5: Jay killed Hae on his own.

This is another popular theory — that Jay acted alone and killed Hae, and that Adnan wasn't involved at all. Adnan has claimed innocence all along.

Reddit drae27 lays out this scenario:

Jay is the local pot dealer. Adnan gives Hae is new cell number the 12th. Adnan sees Hae in school the next day and she hears that Jay has Adnan's car/cell because he is going to buy Stephanie a present. Hae contacts Jay and arranges to meet after school to buy pot. They could have met anywhere. It doesn't have to be Best Buy, but maybe it is. Something bad goes down between Hae and Jay. She confronts him about Stephanie or he comes on to her and in the struggle of fighting him off it gets violent and he strangles her. The Nisha call happens as a "butt" dial in the struggle. Or Jay is trying to call Jen and makes a mistake. (Is there anyway of knowing the speed dial number for Nisha? Does Jen or anyone else's number start with the same number?) Jay leaves the car wherever the incident happened (maybe puts Hae in trunk). Jay goes to pick up Adnan, they get high, go see Kathy, get Adnan to the Mosque, drop Jay off at Jenn's. Jay tells Jenn what happened and asks for help. Either they bury Hae later that night or move the car and do it at another time, possibly with help from a third person.

I don't see this scenario contradicting the call logs. Some will say, why would Jay try to pin it on Adnan when he gets called in since Adnan might have an alibi? My impression of Jay is that he is desperate, a bullshit artist, not too smart and a burn out. It wouldn't surprise me if he just took a stab at it and got lucky.

The motive for Jay is thin, but he is the person most connected to Hae's death other than Adnan.

Theory #6: A serial killer murdered Hae.

Some Redditors have latched onto the theory that Hae's killer was a repeat offender who isn't one of the main players mentioned in the podcast so far.

About six months before Hae was murdered, another teenager from Woodlawn, Jada Denita Lambert, was found strangled and left in a stream in Baltimore. When Hae's body was found, The Baltimore Sun noted the similarities between the two cases and said police would not confirm whether or not they were investigating a link between the two cases.

One significant difference, though, is that Jada was raped and Hae was not.

Police charged a man with Jada's death in 2003. He was 49-year-old convicted robber Roy S. Davis.

Here's Redditor Irkeley's theory about Davis as a suspect:

Wild speculation...

Let's say Adnan is innocent and Jay is lying under threat of drug arrest - then someone else killed Hae Min Lee. In a comment here on reddit it was mentioned that an early news article covering the Lee murder stated that the police had no comment on whether the Lee murder was connected to a murder that happened in Woodlawn seven months earlier (May 1998):

"Authorities would not say whether they are investigating a link between Lee's death and last year's strangulation of Jada Denita Lambert, an 18-year-old Woodlawn woman whose body was found in May in a stream in Northeast Baltimore. Lambert disappeared while driving to work at Mondawmin Mall. No arrest has been made in the case. "

At the time of Adnan's conviction, the 1998 Lambert murder was still unsolved and there were no suspects. Researching the Lambert murder I think it has some similarities to the Lee murder. The victim was 18 years old, she was raped and then murdered by strangulation, and her body was dumped in a stream in Herring Run Park, Baltimore. She was last seen driving home from (or to) the DMV (or work), and she lived on Woodgreen circle in Woodlawn. There were no suspects and the case was unsolved until 2002, when police made a positive DNA match to a guy who was serving time for armed robbery (robbery happened circa april 1999 and he was convicted in june 2000).

The murderer was Roy Sharonnie Davis III, 50, living (at the time) on the 7500 block of Liberty Road in Woodlawn. His criminal record goes back to 1996 and include possession of marijuana, soliciting, making false statement to police, armed robbery, rape and murder.

Since Roy Sharonnie Davis was not convicted until 2002/2004 he was not a suspect during the investigation of the Lee murder in 1999. Could this guy be a potential suspect? From his court records he seemed to be living on the 7500 block of Liberty road during the time of the Lee murder. This address is close to the high school area. By April 1999 he seemed to have moved to a different address (2148 Mt. Royal Terrace).

Roy Sharonnie Davis III is currently serving life in prison for the Lambert murder.

Update: At the time of the murder Roy Sharonnie Davis lived on Hae's route to the daycare. If she took the fastest way there, she must have passed his house. He previously lived one block from the Crown gas station, where the unexplained transaction on Hae's credit card took place. This is a 30 min drive from Woodlawn.

This theory is tempting because it exonerates the people close to Hae, but no solid evidence has been revealed that connects Davis to Hae other than the relative similarities between the two murder cases.