Updated

Today's news of the arrests of Dzhokar Tsarnaev's three friends is really just a sign that investigators are working from the bottom up, from the cleanup crew to hopefully the masterminds.

Two 19-year old friends of suspected Boston Marathon bomber Dzhokar Tsarnaev were charged with a single count of conspiracy to obstruct justice. A third friend was charged with making false statements to federal investigators.

For purposes of clarifying the timeline, on April 15th, two bombs were detonated near the finish line of the Boston Marathon. For days, the perpetrators remained unknown and no terrorist group claimed responsibility.

It was not until three days later, on April 18th, that the FBI released images of the alleged bombers: brothers Tamerlan and Dzhokar Tsarnaev. That night, after a wild goose chase and shootout with police, Tamerlan died of his injuries. On April 19th, Dzhokar was found hiding in a boat and he was taken into custody.

The FBI was clearly on the right path before they found Dzhokar. Also on the 19th, investigators spoke to Dzhokar’s friends, Azamat Tazhayakov and Dias Kadyrbayev. Kadyrbayev told investigators that the day before, on April 18th, he and his two friends helped Dzhokar by disposing of a computer and fireworks-filled backpack from his dorm room.

(The third friend, Robel Phillipos, was also interviewed; however, according to a separate complaint, he lied to authorities over the course of many days, from April 19th until the 25th, about his presence inside of the dorm room and his knowledge about the other friends' behavior. It was not until the 26th that Phillipos confessed that he had previously lied.)

The very next day, on April 20th, authorities took Tazhayakov and Kadyrbayev, both citizens of Kazakhstan, into immigration custody on a “technical violation on a student visa for not regularly attending classes,” according to one of their attorneys. This is a common tactic among law enforcement: if a person can be taken into custody on a legitimate immigration violation, then authorities do not have to worry about the person becoming a flight risk. It also gives authorities time to interview the person about the underlying issue or crime.

The Tazhayakov/Kadyrbayev complaint highlights this tactic as it states that it was not until April 21st, again after the men were in the custody of immigration, that authorities obtained a search warrant into Dzhokar’s dorm room. (Dzhokar’s roommate is unnamed in the complaint.) At this point, authorities did not have to worry about the men disposing of additional evidence.

If convicted, Tazhayakov and Kadyrbayev face up to 5 years in prison, fines, and deportation. The third man, Robel Phillipos, an American citizen, is the only one charged with making false statements to federal investigators. This is a very broad crime. Simply saying, “I don’t know” can lead you to such a charge. He faces up to 8 years in prison and fines but obviously he cannot be deported.

Thus far, nothing suggests the conspiracies alleged between Dzhokar and his three friends include their involvement in the original plot with the Tsarnaev brothers. Instead, the men were apparently just the housekeepers for Dzhokar.

These crimes are very small in comparison to the severity of the ultimate terrorist acts. The Tsarnaev brothers obtained large amounts of explosives, guns, materials, and most importantly, knowledge about how to execute such terrible crimes. Interestingly, Tazhayakov, Kadyrbayev, Phillipos and Tsarnaev all began attending the University of Massachusetts Dartmouth at the same time in 2011. They were friends the entire time and they are all, aside from Phillipos, from a similar region of Eastern Europe. The similarities suggest that the friends know more than what investigators have shared in the complaints.

It is my suspicion that prosecutors charged the three men with minor crimes in an attempt to get more information about the Tsarnaev brothers and, more importantly, their sources of money, intelligence and education.. The friends may hopefully help investigators find those who were involved in planning the crimes, not just the cleanup crew.