CLEVELAND, Ohio -- In the aftermath of the Browns' botched trade for Bengals quarterback AJ McCarron, cleveland.com talked to more than a half-dozen league sources with inside knowledge of how it all went down.

Here's some new details on the front-office edition of the Battle of Ohio, in which the Browns ultimately waited too late to tell the Bengals they wanted to deal.

1. The documents didn't match

After hearing from the Browns shortly before 3:54 p.m. Tuesday that they wanted to make the trade, the Bengals emailed their paperwork to the NFL at 3:55 p.m., just before the 4 p.m. deadline. The Browns, however, didn't send theirs to the NFL. Instead, they sent it to the Bengals at 3:54 p.m. to also sign and send to the league.

The Bengals didn't see the email because it came from Sashi Brown's assistant, Chris Cooper, and was sent to Bengals Player Personnel Director Duke Tobin, who was busy sending his materials to the NFL. He didn't see the email until the following day.

But even if the Browns had copied the NFL on the document sent to the Bengals, the trade wouldn't have been approved -- because the documents didn't match. If the league had received differing documents at 3:55 p.m., there probably wouldn't have been enough time to resolve the matter by 3:59:59.

Even if the terms of the trade were identical -- a second- and third-round pick in 2018 for McCarron, the other language, such as the conditions, was not.

A condition can be something such as "pending McCarron passing his physical..."

The rules are spelled out on Page 54 - Paragraph 8 of the NFL's 2017 Player Personnel Handbook, which states:

"Upon agreeing to a trade, clubs shall exchange written messages of the terms and conditions, after which both clubs are required to notify the Commissioner in writing of such terms and conditions. For any trade to be accepted prior to the deadline of 4:00 p.m., New York time, on each business day, written submissions, including all conditions, must be received by the League office from the involved clubs via the NFL Waivers account, or by FAX, prior to 4:00 p.m., New York time.

"Note: During the Draft, trades will be accepted by telephone communication to the Player Personnel department, provided that written confirmation is transmitted promptly thereafter."

When the Browns received a copy of the Bengals' document at 3:59 p.m., they realized it was different and called the league to appeal. But it was too late. They had run out of time.

2. Mike Brown was the driving force behind the trade in Cincy

Brown, the Bengals' owner, President and GM, was willing to send McCarron to his AFC North foe for two reasons: one, because of his relationship with Hue Jackson, and two, because he likes McCarron and wanted to give him a chance to play.

Others in the Bengals' organization, including Tobin, were less enthusiastic about making the deal because they view McCarron as a valuable asset.

"But no one in the Bengals' organization was standing in the way of getting it done,'' one league source said.

It would have been the first-ever trade between the two clubs, but Brown was willing to do it as long as the compensation was right.

After the 2015 season, Brown tried to persuade Jackson to stay in Cincinnati, where he would've been the heir apparent to longtime friend Marvin Lewis. Instead, he took the Browns' job and is now 1-23 in his second season.

But Brown and Jackson have a good working relationship, and had already executed another trade, for Carson Palmer when Jackson was with the Raiders in 2011. The connection was a major reason this week's deal nearly happened.

3. The deal was off

At about 3:15 p.m. on Tuesday, the trade was dead. The Browns thought draft picks in both the second and third rounds for McCarron, who will either be a restricted or unrestricted free agent after the season depending on arbitration, was too much. They argued that the 49ers gave the Patriots only a second-rounder for Jimmy Garoppolo, who's viewed as the better quarterback.

But Brown, knowing that the Bengals would take heat for the trade because it was with Cleveland, held firm to his asking price.

Besides, the Garoppolo deal for all intents and purposes was for a second-round pick and backup 49ers quarterback Brian Hoyer, who was eventually released and signed by the Patriots for bookkeeping purposes instead of including him in the trade.

4. Then it was back on

Just before 3:54 p.m., the Browns called the Bengals and accepted the deal. Browns owner Jimmy Haslam had gotten involved by that point and signed off on the compensation because he recognized that Jackson's chances to win were undercut by the little talent on the team.

The Browns had also missed out on Garoppolo, whom Jackson coveted, after electing to bypass Carson Wentz and Deshaun Watson in the previous two drafts. The two QBs are tied for the NFL lead with 19 touchdown passes and were named the NFC and AFC Offensive Players of the Month for October, respectively.

On Thursday, Watson suffered a torn ACL in a non-contact situation in practice and is out for the season.

5. The paperwork

The Browns believe they did the right thing when they sent their document to the Bengals, according to a source with knowledge of their process. They would claim that's how they've done all their trades over the past two years -- send their signed trade agreement to the other team, have them sign it and send it to the league.

Again, the league's guidelines state that "Upon agreeing to a trade, clubs shall exchange written messages of the terms and conditions, after which both clubs are required to notify the Commissioner in writing of such terms and conditions."

The Browns sent their "written message" to the Bengals, who didn't see it in time.

Here's where it went awry: The Browns called the Bengals too late to properly execute the deal, and it fell through. Had they accepted the terms earlier, even by 10 to 15 minutes, they could've worked out the kinks.

Instead, the Bengals had about five minutes to get their paperwork in once they finally heard from the Browns.

One source said, "the Bengals would never have had time to read the Browns' document, sign it, and get it to the league. They did they right thing. They fired off their own paperwork to the NFL and got it in on time.''

The Browns and Bengals also apparently weren't on the same page on the terms and conditions of the trade. Or if they were, they didn't clearly articulate to each other what they were including in their documents.

The signals got crossed and the trade was botched.

Meanwhile, the Panthers dealt receiver Kelvin Benjamin to the Bills -- at 3:57 p.m. -- so it's possible to pull it off at the last minute.

It might've also helped if the email to Cincy came from Brown instead of Cooper, an unrecognized name. Regardless, the Bengals might not have seen it in time while scrambling to send in their paperwork -- which they did in a matter that's perfectly acceptable to the NFL providing their trade partner does likewise.

The clubs probably should've also stayed on the phone until they knew they had identical documents going to the league on time.

If they had, the trade would've gone through. One source said the league isn't too particular on deadline as long as it hears from both teams and the terms and conditions match.

"I don't know that I've ever really heard of one (blowing up like this)," Marvin Lewis said in his press conference Wednesday. "All you have to do is notify the league office you're making a deal. And that's an easy thing."

6. The formal trade papers

Sources say the Browns were apparently trying to complete paperwork for the trade that doesn't need to be submitted until 15 days after the deal. That paperwork is signed by both clubs and sent to the league and to each team.

The Browns say both teams had to send in one document signed by both before Tuesday's trade deadline -- but multiple league sources say each team is required to send in their own written notification, with matching terms and conditions.

Still, if the NFL had received official written word from the Browns before 4 p.m., they may have been able to take a minute or two to correct the discrepancy in the language. Instead, they ran out of time.

The moment the Bengals received word from the Browns at 3:54 that they wanted to do the deal, they called the NFL office and told them the trade was on and to look for the Bengals' paperwork coming via email.

The Bengals assumed the Browns were following the same protocol.

7. Did the Browns' front office really want to do this deal?

The Browns had a chance to trade for McCarron ever since the trade window opened in March. The Bengals didn't really want to do the deal back then, but would've considered it for the same reasons they did Tuesday: Brown's strong relationships with Jackson and McCarron.

"It's not ideal to trade guys within your division, particularly at that position, but we'll listen,'' Tobin said at the NFL Combine in February.

Tobin received an inquiry from the Browns that they were interested in McCarron, but he never received an offer. It's not known who approached him, but if it was Jackson, the front office might not have been on board.

Jackson had pushed hard all offseason for Garoppolo, and then for McCarron when it became apparent the Patriots either didn't want to part with Garoppolo at that time, or were asking too much.

But Sashi Brown made it clear throughout the spring that the Browns had no plans to trade for a veteran quarterback. In the end, it was a sign of a growing rift between the coaching staff and the front office. The coaches wanted a veteran QB, and the front office didn't.

"The Browns had months to trade for AJ if they really wanted him,'' a source said.

League sources speculate the Browns pushed it up the limit knowing they might not be able to pull it off. But sources close to the Browns, however, insist that wasn't the case and that everyone -- including Brown and Jackson -- were working feverishly to get it done. They just started the process too late.

8. Losing Garoppolo

It's unknown if the Browns called the Patriots before the trade deadline to try to acquire Garoppolo, whom they tried to obtain during the draft. The Browns have three second-round picks in 2018, and likely could've outbid the 49ers.

Some speculate that Bill Belichick didn't want his star backup playing in the AFC.

But as for a report by 104.7 FM Denver's Benjamin Allbright that Sashi Brown was home by 5 p.m. Monday when the Garoppolo news was coming down, a source said that's false. Instead, the assistant coaches were sent home early that night after returning home at about 1 a.m. from London.

The Patriots might have preferred doing a deal with the 49ers, because it enabled them to replace Garoppolo with Brian Hoyer, the former Browns quarterback who began his career in New England.

In the end, the 49ers ended up with their possible quarterback of the future, and the Browns are still searching for theirs.