The media theory over the last several days about the Boston Marathon bombing is that the pressure-cooker design came straight off the Internet and didn’t require any specific training.  That assumption ignores a couple of key points even if the bomb design matched those readily available on jihadi websites, such as practice and testing, of which so far the FBI has found no evidence in the US.  Second, any deviation from those designs would entirely negate that kind of “lone wolf” scenario — and according to the Wall Street Journal, the FBI now believes that Tamerlan Tsarnaev had to have received assistance and/or training for the designs he used:

A Federal Bureau of Investigation analysis of the bombs used in the Boston Marathon attacks has concluded that makers of the devices had some knowledge beyond the step-by-step recipes already described by the surviving suspect in the attack.

Dzhokhar Tsarnaev has told interrogators that he and his brother used bomb-making instructions found in Inspire, an online al Qaeda magazine, according to federal officials. His brother, Tamerlan Tsarnaev, the other accused bomber, was killed during a gunfight with police in Watertown, Mass.

The FBI’s bomb experts analyzed remnants of both bombs that exploded on April 15 near the marathon’s finish line, as well as additional explosive devices that authorities said were recovered after the encounter with the suspects early on April 19.

Their early conclusion is that the bomb makers likely had additional training or expertise, in part because they deviated from two recipes in Inspire, according to a report prepared by the Terrorist Explosive Device Analytical Center and law-enforcement officials briefed on the investigation.

The analysis also determined that the explosives used were “consistent with commercial fireworks,” said the report, which was reviewed by The Wall Street Journal. Officials cautioned that the analysis was preliminary.

Boston PD found a cache of discarded fireworks on Wednesday night, many with the gunpowder removed.  That would connect with the design of the bomb, although investigators have yet to link the find directly to the Tsarnaevs — yet, anyway.

This does, however, point up the importance of finding what the Tsarnaevs preferred to throw away.  With one of the bombing suspects dead and the other in a prison hospital facility, investigators of the Boston Marathon terrorist attack have access to the possessions of the two Tsarnaevs. What about those items that left their possession just before the bombing? CBS News’ John Miller updated viewers on the investigation and reported that FBI agents are now searching for laptops that the two brothers discarded shortly before conducting their attack:

FBI agents picked through a landfill near the University of Massachusetts Dartmouth, where 19-year-old suspect, Dzhokhar Tsarnaev, was a sophomore.

On “CBS This Morning: Saturday,” CBS News senior correspondent John Miller, a former assistant FBI director, reports the agents were looking for a couple of laptop computers that belonged to the suspects.

“One of the things in these terrorism cases, particularly, Margaret, where the issue is how did a process of radicalization occur, a lot of that occurs online,” Miller told CBS News correspondent Margaret Brennan, “particularly where they want to know was anyone else involved, was there a mastermind, was he communicating with someone overseas about it.”

Miller reports that investigators believe those answers are likely to be found in the computers.

“They believe that what they learned from the brother was that the computer was tossed just before the bombing mission, probably to conceal all that, so they’d really like to get it back,” Miller said.

Earlier, we noted the FBI’s landfill search, which was reported in the context of looking for staging areas for bomb tests. This adds another level of interest in landfills, but the FBI will need a lot of luck in finding evidence in either effort. The search began, apparently, when Dzhokhar admitted discarding the laptops, and presumably they have a good idea where that took place. Still, actually finding the laptops would still be a challenge, and it’s at least a good possibility that the two were technically adept enough to destroy the hard drives before discarding the computers.

Speaking of technology, it’s not just discarded physical assets that investigators want to find. The FBI has found the little-known Instagram account of Dzhokhar, and preliminary information shows that he was very interested in a dead Chechen warlord and terrorist leader:

Dzhokhar Tsarnaev’s Twitter account and VK Russian social networking profile have drawn heavy public scrutiny, but he left another, more hidden social media trail: a deleted Instagram account that sources close to him tell CNN once belonged to the accused Boston bomber.

The Instagram account, with the user name “jmaister1,” no longer exists, and friends of Tsarnaev say it was deleted only recently. An Instagram spokesman declined to comment on the account or disclose when the account was deleted.

CNN National Security Analyst Juliette Kayyem says the account could be significant.

“If I were an investigator right now, obviously the platform he deleted matters the most,” she said.

Indeed. The last activity they have found (so far) before Dzhokhar deleted the account took place on April 10th, when “jmaister1” liked a picture and profile of Shamil Basayev, a long-dead Chechen warlord and terrorist.  Among other items on Basayev’s resumé is the Beslan massacre, in which more than 380 people were killed, most of them schoolchildren, and hundreds more wounded.  Basayev financed and organized the terrorist attack, later bragging that it had only cost him 8,000 rubles for the whole operation.  Russians put a $10 million bounty on Basayev’s head; he later died when a mine he was inspecting detonated unexpectedly.  The FSB insinuated that they had a hand in the detonation.

As Kayyem correctly points out, the fact that Dzhokhar had an Instagram account is interesting, and his “like” of Basayev intriguing.  Far more interesting is what they haven’t found — and why Dzhokhar went out of his way between April 10th and April 14th to delete the account.  Finding their discards might end up being the quickest path to understanding the true nature of the bombers and the bombing.