“Dallas” drops tantalizing new clues in the “Who Killed J.R.?” mystery throughout “Let Me In,” the TNT drama’s latest episode. Here’s a look at what we know and what we don’t, along with some more wild speculation.

J.R.’S MASTER PLAN

What we know: In “Let Me In,” Bobby (Patrick Duffy) lets Sue Ellen (Linda Gray) in on a big secret: Before J.R. died, he was devising a master plan against the family’s enemies, Cliff and Harris (Ken Kercheval, Mitch Pileggi). Bobby shows Sue Ellen the evidence that J.R. left behind and gives her a helpful overview of her ex-husband’s scheme. Take it away, Bobby:

“J.R. knew that Cliff and Harris would join forces and come after us. That’s why he wanted us to have this – all pieces to the puzzle of his master plan to take them down, once and for all. Barnes Global financial history. Ryland’s trucking in Mexico. Christopher’s mother’s whereabouts. Somehow it’s all connected. John Ross, Christopher and I are trying to figure it all out. Connect the dots. Finish what J.R. started. We need to find a way to ruin them, before they ruin us.”

What we don’t know: Assuming Bobby is reading the clues correctly, we now know all the pieces belong to the same puzzle. The question is, how do they fit together?

Wild speculation: One Dallas Decoder reader offered a nifty theory last week. We know Pam (Victoria Principal) fled Southfork in 1987 after being disfigured in a fiery car crash. Suppose that incident is part of the conspiracy J.R. stumbled upon before his death? Remember: Pam crashed into a tanker truck. And who on “Dallas” is in the trucking business? Harris Ryland, of course! I have no idea why he would want to harm Pam, but this coincidence is too fun to ignore.

PAM

What we know: After learning Pam was last seen in Abu Dhabi in 1989, Bobby told John Ross and Christopher (Josh Henderson, Jesse Metcalfe) that his contact in the Justice Department is tracking her down but needs more time. Later, John Ross snooped around Pamela’s computer and found a copy of her grandmother Rebecca Wentworth’s will, which John Ross reviewed with Bobby, Sue Ellen and Christopher.

The will shows Rebecca left her estate – including her shares of Barnes Global – to her three children: Katherine, Cliff and Pam. Bobby determined the estate is in a living trust, which means if the Ewings can’t find Pam, Christopher will inherit her shares. “If we can get Pam’s shares, we can kick the legs out from under Cliff. Maybe his entire plan. That’s why J.R. wanted us to find Pam. That’s our move,” Bobby said.

What we don’t know: In a previous episode, we learned Katherine is dead. If this is true, who inherited her third of Barnes Global and why isn’t anyone asking about that? (Or does the living trust arrangement render that point moot? Help me out here, legal eagles.)

Wild speculation: I still like the idea that Katherine (Morgan Brittany) stole Pam’s identity before she died and that this whole thing is going to lead to nutty Ms. Wentworth. It seems unlikely, though, since Brittany recently told Dallas Divas Derby she hasn’t been contacted by the show’s execs. I’m also not sure the Ewings are going to find Pam alive. Given Cliff’s dark nature, isn’t it possible he offed Pam, perhaps in cahoots with her plastic surgeon Dr. David Gordon, who is expected to resurface before this season is over?

Another off-the-wall theory: Instead of bringing back Pam or Katherine, what if “Dallas” revives a member of the Barnes family who’ll be more familiar to today’s audience: Frank Ashkani (Faran Tahir), Cliff’s “adopted” son, who killed himself earlier this season? One Dallas Decoder reader recently suggested the pills Frank swallowed might not have been all that lethal. Could Cliff have conspired with Frank to fake his death so Frank could go to Mexico and kill J.R.?

‘LADY X’

What we know: After J.R.’s death in Nuevo Laredo, a Mexican border town, his friend Carlos del Sol (Castulo Guerra) told the Ewings that J.R. met a woman in a club near the hotel where he died. I previously dubbed this woman “Lady X.” In “Let Me In,” we learn her identity: Rhonda (Emily Kosloski), the club hostess. She tells Bobby that J.R. wanted to ask her about an American who frequented the club, which she said was owned by the local drug cartel. When Bobby showed her a picture of Harris, Rhonda identified him as the American in question.

“What would Ryland be doing with narco traffickers? Is that what his trucks are taking back and forth across the border? Maybe J.R. was on to that,” Bobby said. Carlos responded he would alert the Mexican federales and “let them know there may be a connection between the cartel and Ryland Transport.”

What we don’t know: Are Carlos and Rhonda telling the truth? All along, I’ve suspected Carlos is somehow involved in J.R.’s death. And what should we make of the odd expression on Bobby’s face after Rhonda tells him, “J.R.’s not the first man to invite me back to his hotel room. He just wanted to talk. Share a drink. He was kind to me. Gentlemen are in such short supply where I work. I’m so sorry, what happened to your brother.”

Wild speculation: What if Cliff is the killer and has secretly aligned himself with Carlos, a fellow billionaire, to frame Harris for the crime? Consider this: Why would Cliff, a global titan, need to join forces with Harris, a Texas trucking magnate, to bring down the Ewings? I know Cliff told Harris he wanted to take advantage of Harris’s “muscle” and friendship with the governor, but Cliff has demonstrated he has those kinds of resources and connections himself. Could Cliff be duping Harris?

On the other hand: The Rylands seem to have real connections to the Mexican border. Did you catch the Laredo address on the pill bottle Emma showed John Ross at J.R.’s funeral?

THE GUN AND THE LETTER

What we know: When J.R.’s private eye Bum (Kevin Page) gave Bobby, John Ross and Christopher the evidence that J.R. left behind, the package included a gun, which was accompanied by a letter from J.R. to John Ross. It stated: “Use what I’ve given you to take from them what they want to take from us. When you’ve done that, Bobby will know what to do.”

J.R. also left behind a letter to Bobby, which he refused to discuss with John Ross and Christopher. “This is between my brother and me – for now,” Bobby told them. Privately, Bobby told Bum to “pay off whoever you have to pay off so that everybody still thinks J.R. was killed by a mugger. When the time comes, we’ll take care of this ourselves – as a family.”

What we don’t know: Precious little. I don’t think the letter reveals the identity of J.R.’s killer; otherwise, why isn’t Bobby simply going after that person? Instead, I think the document somehow lets Bobby know that J.R. wasn’t the victim of a random crime. Or perhaps it reveals something else – like maybe some sort of family secret? Recall what Bobby said when he toasted his dead brother after receiving the note: “I knew you’d have at least one more left up your sleeve, J.R. It is a good one. I love you brother.”

Wild speculation: Once again, I return to the theory that J.R. planned his own death. I know a lot of fans don’t like this idea, but it seems like you can use the available evidence to support it. Suppose J.R. knew that he was dying and decided to take advantage of the situation by arranging to have himself shot, then leaving instructions for Bobby – via the letter – to use the gun to frame Cliff, Harris or both for his “murder”? Perhaps Bobby’s last line in his recap for Sue Ellen is telling: “We need to find a way to ruin them, before they ruin us.”

Or hell, maybe it really was Kristin.

Who done it? Share your theories below and read more posts on Dallas Decoder’s “Who Killed J.R.?” page.